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On April 20, 2018, the Kween District Health Office in Kween District, Uganda reported 7 suspected cases of human anthrax. A team from the Uganda Ministry of Health and partners investigated and identified 49 cases, 3 confirmed and 46 suspected; no deaths were reported. Multiple exposures from handling the carcass of a cow that had died suddenly were significantly associated with cutaneous anthrax, whereas eating meat from that cow was associated with gastrointestinal anthrax. Eating undercooked meat was significantly associated with gastrointestinal anthrax, but boiling the meat for >60 minutes was protective. We recommended providing postexposure antimicrobial prophylaxis for all exposed persons, vaccinating healthy livestock in the area, educating farmers to safely dispose of animal carcasses, and avoiding handling or eating meat from livestock that died of unknown causes.

BackgroundOn 23 February 2018, the Uganda Ministry of Health (MOH) declared a cholera outbreak affecting more than 60 persons in Kyangwali Refugee Settlement, Hoima District, bordering the Democratic Republic of Congo (DRC). We investigated to determine the outbreak scope and risk factors for transmission, and recommend evidence-based control measures.MethodsWe defined a suspected case as sudden onset of watery diarrhoea in any person aged ≥ 2 years in Hoima District, 1 February–9 May 2018. A confirmed case was a suspected case withVibrio choleraecultured from a stool sample. We found cases by active community search and record reviews at Cholera Treatment Centres. We calculated case-fatality rates (CFR) and attack rates (AR) by sub-county and nationality. In a case-control study, we compared exposure factors among case- and control-households. We estimated the association between the exposures and outcome using Mantel-Haenszel method. We conducted an environmental assessment in the refugee settlement, including testing samples of stream water, tank water, and spring water for presence of fecal coliforms. We tested suspected cholera cases using cholera rapid diagnostic test (RDT) kits followed by culture for confirmation.ResultsWe identified 2122 case-patients and 44 deaths (CFR = 2.1%). Case-patients originating from Demographic Republic of Congo were the most affected (AR = 15/1000). The overall attack rate in Hoima District was 3.2/1000, with Kyangwali sub-county being the most affected (AR = 13/1000). The outbreak lasted 4 months, which was a multiple point-source. Environmental assessment showed that a stream separating two villages in Kyangwali Refugee Settlement was a site of open defecation for refugees. Among three water sources tested, only stream water was feacally-contaminated, yielding > 100 CFU/100 ml. Of 130 stool samples tested, 124 (95%) yieldedV. choleraeby culture.Stream water was most strongly associated with illness (odds ratio [OR] = 14.2, 95%CI: 1.5–133), although tank water also appeared to be independently associated with illness (OR = 11.6, 95%CI: 1.4–94). Persons who drank tank and stream water had a 17-fold higher odds of illness compared with persons who drank from other sources (OR = 17.3, 95%CI: 2.2–137).ConclusionsOur investigation demonstrated that this was a prolonged cholera outbreak that affected four sub-counties and two divisions in Hoima District, and was associated with drinking of contaminated stream water. In addition, tank water also appears to be unsafe. We recommended boiling drinking water, increasing latrine coverage, and provision of safe water by the District and entire High Commission for refugees.

Background SARS-CoV-2 has been identified in the fecal matter of COVID-19 patients. However, sewage transmission has never been shown. In April 2020, a COVID-19 outbreak occurred in a densely populated community in Guangzhou, China. We investigated this outbreak to identify the mode of transmission. Method A home quarantined order was issued in the community. We collected throat swab samples from the residents and environmental samples from the surfaces inside and around the houses, and conducted RT-PCR testing and genome sequencing. We defined a case as a resident in this community with a positive RT-PCR test, with or without symptoms. We conducted a retrospective cohort study of all residents living in the same buildings as the cases to identify exposure risk factors. Result We found eight cases (four couples) in this community of 2888 residents (attack rate=2.8/1000), with onset during April 5–21, 2020. During their incubation periods, Cases 1-2 frequented market T with an ongoing outbreak. Cases 3-8 never visited market T during incubation period, lived in separate buildings from, and never interacted with, Cases 1-2. Retrospective cohort study showed that working as cleaners or waste picker (RR=13, 95% CIexact: 2.3-180), not changing to clean shoes after returning home (RR=7.4, 95% CIexact: 1.8-34), collating and cleaning dirty shoes after returning home (RR=6.3, 95% CIexact: 1.4-30) were significant exposure risk factors. Of 63 samples collected from street-sewage puddles and sewage-pipe surfaces, 19% tested positive for SARS-CoV-2. Of 50 environmental samples taken from cases’ apartments, 24% tested positive. Viral genome sequencing showed that the viruses identified from the squat toilet and shoe-bottom dirt inside the apartment of Cases 1-2 were homologous with those from Cases 3-8 and those identified from sewage samples. The sewage pipe leading from the apartment of Cases 1-2 to the drainage had a large hole above ground. Rainfalls after the onset of Cases 1-2 flooded the streets. Conclusion Our investigation has for the first time pointed to the possibility that SARS-CoV-2 might spread by sewage. This finding highlighted the importance of sewage management, especially in densely-populated places with poor hygiene and sanitation measures, such as urban slums and other low-income communities in developing countries.

Background Kampala city slums, with one million dwellers living in poor sanitary conditions, frequently experience cholera outbreaks. On 6 January 2019, Rubaga Division notified the Uganda Ministry of Health of a suspected cholera outbreak in Sembule village. We investigated to identify the source and mode of transmission, and recommended evidence-based interventions. Methods We defined a suspected case as onset of profuse, painless, acute watery diarrhoea in a Kampala City resident (≥ 2 years) from 28 December 2018 to 11 February 2019. A confirmed case was a suspected case with Vibrio cholerae identified from the patient’s stool specimen by culture. We found cases by record review and active community case-finding. We conducted a case–control study in Sembule village, the epi-center of this outbreak, to compare exposures between confirmed case-persons and asymptomatic controls, individually matched by age group. We overlaid rainfall data with the epidemic curve to identify temporal patterns between rain and illnesses. We conducted an environmental assessment, interviewed village local council members, and tested water samples from randomly-selected households and water sources using culture and PCR to identify V. cholerae. Results We identified 50 suspected case-patients, with three deaths (case-fatality rate: 6.0%). Of 45 case-patients with stool samples tested, 22 were confirmed positive for V. cholerae O1, serotype Ogawa. All age groups were affected; persons aged 5–14 years had the highest attack rate (AR) (8.2/100,000). The epidemic curve showed several point-source outbreaks; cases repeatedly spiked immediately following rainfall. Sembule village had a token-operated water tap, which had broken down 1 month before the outbreak, forcing residents to obtain water from one of three wells (Wells A, B, C) or a public tap. Environmental assessment showed that residents emptied their feces into a drainage channel connected to Well C. Drinking water from Well C was associated with illness (ORM–H = 21, 95% CI 4.6–93). Drinking water from a public tap (ORM–H = 0.07, 95% CI 0.014–0.304) was protective. Water from a container in one of eight households sampled tested positive for V. cholerae; water from Well C had coliform counts ˃ 900/100 ml. Conclusions Drinking contaminated water from an unprotected well was associated with this cholera outbreak. We recommended emergency chlorination of drinking water, fixing the broken token tap, and closure of Well C.

Background Few cases of organophosphate poisoning in developing countries have been investigated using clinical and epidemiological methods. On 30 October 2015, 3 students at Mukuju School, Tororo District, Uganda, died soon after eating chapatti (locally-made flat bread) from the same food stand. Ministry of Health investigated to identify the cause and recommend prevention measures. Methods We defined a case as onset during 30–31 October 2015 in a resident of Mukuju Town of ≥1 of the following symptoms: excessive saliva, profuse sweating, dizziness, low blood pressure, constricted pupils or loss of consciousness. We reviewed medical/police records and interviewed survivors, healthcare workers, and police officers. We collected samples of implicated food for toxicological analysis. Autopsies were performed on decedents to identify the cause of death. Results We identified 7 cases with 3 deaths (case-fatality ratio = 43%). Clinical manifestations included acute onset of confusion (100%), constricted pupils (43%), excessive saliva (43%), and low blood pressure (43%). All 7 cases had onset from 16:00–18:00 h on 30 October, with a point-source exposure pattern. Of the 7 cases, 86% (6/7) were men; the mean age was 24 (range: 20–32) years. The 3 decedents each ate a whole chapatti while the other 4 cases ate half or less. Autopsy findings of the 3 decedents indicated organophosphate poisoning. Toxicological analysis found high levels of malathion in leftover foods (266 mg/L in dough and 258 mg/L in chapatti) and malaoxon (a highly toxic malathion derivative) in decedents’ postmortem specimens (mean levels of 19 mg/L in the blood and 22 mg/L in the gastric contents). There was a delay of 4 h before the patients received appropriate treatment. Police investigations revealed that flour used to make the chapatti was intentionally contaminated with an organophosphate pesticide. Conclusion This fatal outbreak of organophosphate poisoning was associated with consumption of roadside-vended chapatti made of flour contaminated with pesticide. Clinicians should be aware of symptoms of organophosphate poisoning and prepared to treat it quickly. Street vendors should carefully consider the source of their ingredients. An in-depth surveillance review of such poisonings in Uganda would guide policymakers in reducing access by criminals and accidental exposures for the public. Electronic supplementary material The online version of this article (10.1186/s12889-019-7143-0) contains supplementary material, which is available to authorized users.

Cassava (Manihot esculenta), an edible tuberous root that is resistant to drought, diseases, and pests, is a major source of carbohydrates in tropical areas, the second most widely grown and consumed food in Uganda after bananas, and a staple in the diet for approximately 57% of the Uganda population (Figure 1) (1). On September 5, 2017, a funeral was held in Kasese District in western Uganda. Following the funeral, 33 persons with symptoms that included diarrhea, vomiting, and abdominal pains were admitted to Bwera Hospital in Kasese District. On September 8, the Uganda Ministry of Health received notification from the Kasese District health team regarding this outbreak of suspected food poisoning. An investigation to determine the cause of the outbreak and recommend control measures revealed that the outbreak resulted from consumption of a cassava dish made by combining hot water with cassava flour. The implicated batch of cassava flour was traced back to a single wholesaler and found to contain high cyanogenic content. Informed by the investigation findings, police confiscated all cassava flour from retailers identified as the patients' source of the flour. Health education about cyanide poisoning from cassava and the need to adequately process cassava to reduce cyanogenic content was conducted by public health officials.

Background Jimsonweed (Datura stramonium) contains toxic alkaloids that cause gastrointestinal and central nervous system symptoms when ingested. This can be lethal at high doses. The plant may grow together with leguminous crops, mixing with them during harvesting. On 13 March 2019, more than 200 case-patients were admitted to multiple health centres for acute gastrointestinal and neurologic symptoms. We investigated to determine the cause and magnitude of the outbreak and recommended evidence-based control and prevention measures. Methods We defined a suspected case as sudden onset of confusion, dizziness, convulsions, hallucinations, diarrhoea, or vomiting with no other medically plausible explanations in a resident of Napak or Amudat District from 1 March—30 April 2019. We reviewed medical records and canvassed all villages of the eight affected subcounties to identify cases. In a retrospective cohort study conducted in 17 villages that reported the earliest cases, we interviewed 211 residents about dietary history during 11–15 March. We used modified Poisson regression to assess suspected food exposures. Food samples underwent chemical (heavy metals, chemical contaminants, and toxins), proteomic, DNA, and microbiological testing in one national and three international laboratories. Results We identified 293 suspected cases; five (1.7%) died. Symptoms included confusion (62%), dizziness (38%), diarrhoea (22%), nausea/vomiting (18%), convulsions (12%), and hallucinations (8%). The outbreak started on 12 March, 2–12 h after Batch X of fortified corn-soy blend (CSB +) was distributed. In the retrospective cohort study, 66% of 134 persons who ate CSB + , compared with 2.2% of 75 who did not developed illness (RRadj = 22, 95% CI = 6.0–81). Samples of Batch X distributed 11–15 March contained 14 tropane alkaloids, including atropine (25-50 ppm) and scopolamine (1-10 ppm). Proteins of Solanaceae seeds and Jimsonweed DNA were identified. No other significant laboratory findings were observed. Conclusion This was the largest documented outbreak caused by food contamination with tropane alkaloids. Implicated food was immediately withdrawn. Routine food safety and quality checks could prevent future outbreaks.

Background Measles is a highly infectious viral disease. In August 2017, Lyantonde District, Uganda reported a measles outbreak to Uganda Ministry of Health. We investigated the outbreak to assess the scope, factors facilitating transmission, and recommend control measures. Methods We defined a probable case as sudden onset of fever and generalized rash in a resident of Lyantonde, Lwengo, or Rakai Districts from 1 June-30 September 2017, plus ≥1 of the following: coryza, conjunctivitis, or cough. A confirmed case was a probable case with serum positivity of measles-specific IgM. We conducted a neighborhood- and age-matched case-control study to identified exposure factors, and used conditional logistic regression to analyze the data. We estimated vaccine effectiveness and vaccination coverage. Results We identified 81 cases (75 probable, 6 confirmed); 4 patients (4.9%) died. In the case-control study, 47% of case-patients and 2.3% of controls were hospitalized at Lyantonde Hospital pediatric department for non-measles conditions 7–21 days before case-patient’s onset (ORadj = 34, 95%CI: 5.1–225). Estimated vaccine effectiveness was 95% (95%CI: 75–99%) and vaccination coverage was 76% (95%CI: 68–82%). During the outbreak, an “isolation” ward was established inside the general pediatric ward where there was mixing of both measles and non-measles patients. Conclusions This outbreak was amplified by nosocomial transmission and facilitated by low vaccination coverage. We recommended moving the isolation ward outside of the building, supplemental vaccination, and vaccinating pediatric patients during measles outbreaks.

Introduction Gastrointestinal anthrax is a rare but serious disease. In August 2017, Isingiro District, Uganda reported a cluster of >40 persons with acute-onset gastroenteritis. Symptoms included bloody diarrhoea. We investigated to identify the etiology and exposures, and to inform control measures. Methods We defined a suspected case as acute-onset of diarrhoea or vomiting during 15–31 August 2017 in a resident (aged≥2 years) of Kabingo sub-county, Isingiro District; a confirmed case was a suspected case with a clinical sample positive for Bacillus anthracis by culture or PCR. We conducted descriptive epidemiology to generate hypotheses. In a case-control study, we compared exposures between case-patients and neighbourhood-matched controls. We used conditional logistic regression to compute matched odds ratios (MOR) for associations of illness with exposures. Results We identified 61 cases (58 suspected and 3 confirmed; no deaths). In the case-control study, 82% of 50 case-patients and 12% of 100 controls ate beef purchased exclusively from butchery X during the week before illness onset (MOR = 46, 95%CI = 4.7–446); 8.0% of case-patients and 3.0% of controls ate beef purchased from butchery X and elsewhere (MOR = 19, 95%CI = 1.0–328), compared with 6.0% of case-patients and 30% of controls who did not eat beef. B. anthracis was identified in two vomitus and one stool sample. Butchery X slaughtered a sick cow and sold the beef during case-patients’ incubation period. Conclusion This gastrointestinal anthrax outbreak occurred due to eating beef from butchery X. We recommended health education, safe disposal of the carcasses of livestock or game animals, and anthrax vaccination for livestock., Author summary Gastrointestinal anthrax is one of the forms of anthrax caused by Bacillus anthracis. It is a serious but rarely diagnosed form owing to its presentation being similar to gastroenteritis illness due to other organisms. In this investigation, we ascertained that this was a gastrointestinal anthrax outbreak that was caused by consumption of beef of suspicious origin. Trace back identified the source of this beef as being from one specific butcher. All the case-patients were treated and recovered. The outbreak was controlled at the source through treatment and we provided public education of the masses about the dangers of eating meat of animals that have died of unknown causes. We additionally recommended inspection of meat before sale at butcheries to ensure that it is suitable for human consumption as well as vaccination of the animals in the region. In the long term, anthrax control requires a One-Health approach that is multisectoral, involving ministries of agriculture, animal industries and ministries of health.

Background During January 2017-December 2018, multiple human anthrax outbreaks in Arua, Kween, and Kiruhura districts, Uganda were caused by exposure to domestic ruminants that died of anthrax. We investigated to determine the scope of anthrax outbreaks in domestic ruminants, identify possible exposures, and recommend evidence-based control measures. Methods We defined a suspected case-animal as sudden death of a domestic ruminant with unclotted blood oozing from body orifices during January 2016–December 2018 in Arua, Kween and Kiruhura districts. A probable case-animal was a suspected case-animal with a positive rapid diagnostic test using the Active Anthrax Detect Rapid Diagnostic Test, and/or the microscopic identification of Gram-positive rods in biological samples. A case-kraal was defined as an enclosure of cattle/sheep or mixed species with ≥1 suspected case-animal. We reviewed district veterinary records and actively searched for case-livestock. We conducted separate case-control studies in the affected districts to compare exposures between case-kraals and control-kraals (i.e., kraals with no suspected case-livestock during the same time period as the case-kraal), frequency-matched by village, with ratios of 1:1 in Arua, 1:4 in Kiruhura, and 1:2 in Kween. We estimated overall associations in all three districts using pooled analysis. Results We identified 1,971 suspected case-livestock (attack rate [AR] =1.4/1000) in 229 (7.3/1,000) of 31,500 kraals. Cattle (AR=2.1/1,000), goats (AR=0.48/1,000), and sheep (AR=0.10/1,000) were all affected. Of the three districts, Arua was the most affected (AR=3.1/1,000), followed by Kween (AR=1.8/1,000) and Kiruhura (AR=0.065/1,000). The epidemic curve indicated continuous outbreaks in Arua and Kween districts. Human outbreaks were reported during or after the onset of livestock outbreaks in all three districts. Having livestock that died of suspected anthrax butchered

Background: SARS-CoV-2 has been identified in the feces of COVID-19 patients. However, fecal transmission has never been shown epidemiologically. In April 2020, a COVID-19 outbreak occurred in a low-income community in Guangzhou, China. We investigated this outbreak to identify the mode of transmission. Methods: A home quarantined order was issued in the community. We collected throat swab samples from the residents and environmental samples from the surfaces inside and around the houses, and conducted RT-PCR testing and genome sequencing. We defined a case as a resident in this community with a positive RT-PCR test. We conducted a retrospective cohort study among the residents living in the same building as the cases to identify transmission risk factors. Findings: We found eight cases (four couples) in this community of 2888 residents (attack rate=2.8/1000), with onset from April 5 to 21, 2020. During their incubation periods, Cases 1 and 2 frequented a Market T, where an outbreak was ongoing. Cases 3-8 never visited Market T during incubation periods, lived in separate buildings from, and never interacted with, Cases 1 and 2. Retrospective cohort study showed that working as cleaners or street scavengers (RR=13, 95% CI: 1.8-99), not changing to clean shoes after returning home (RR=7.4, 95% CI: 1.7-33), collating and cleaning dirty shoes after returning home (RR=6.3, 95% CI: 1.4-28) were significant exposure risk factors. Of 63 samples collected from street sewage puddles and sewage pipes, 19% tested positive for SARS-CoV-2. Of 50 samples taken from the cases’ apartments, 24% tested positive. RNA sequencing showed that the viruses identified from the squat toilet and the shoe-bottom dirt from the apartments of Cases 1 and 2 are homologous with those from Cases 3-8 and those identified from the sewage samples. The sewage pipe leading from the apartment of Cases 1 and 2 down to the drainage had a large crack above the ground. Rainfalls after the onset of Cases 1 and 2 flooded the streets. Interpretation: Our investigation has for the first time provided epidemiologic evidence that SARS-CoV-2 can be spread by sewage. This finding highlighted the importance of sewage management, especially in densely-populated places with poor hygiene and sanitation measures, such as urban slums and other low-income communities in developing countries. Funding: No. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: This study was approved by the ethics committees of GZCDC (approval number GZCDC-ECHR-2020A0004).

On October 25, 2016, media reports alerted the Uganda Ministry of Health to an outbreak of >80 cases of vomiting, syncope, and acute diarrhea among workers at a flower farm in central Uganda; 27 workers were hospitalized. On November 1, an investigation was undertaken by the Uganda Public Health Fellowship Program.* A case-control study found that working inside greenhouse 7, which had been fumigated with the organosulfur compound metam sodium the night of October 13, was strongly associated with illness. Employees who worked in this greenhouse during October 14-21 reported a strong "suffocating" smell in the greenhouse. Investigation revealed that, in violation of safety protocols, workers did not properly cover the soil after fumigation, allowing vapors to become trapped inside the greenhouse. The farm management, unaware of the lapse, failed to inform workers to avoid the vicinity of the fumigation. Respiratory protective measures were not routinely available for workers, which likely contributed to the severity and extent of the outbreak. Although metam sodium is generally considered to be of low risk when used according to manufacturer's instructions (1), occupational exposure in the absence of recommended safety measures can have serious health consequences. The investigation highlighted the importance of identifying potential occupational hazards to workers, as well as establishing safety protocols in occupational settings, training workers at risk, such as pesticide sprayers and flower pickers,† and ensuring enforcement of safety protocols. After this outbreak, the farm management reviewed, revised, and trained the workers on safety protocols to prevent future outbreaks.

Background In May 2015, a cholera outbreak that had lasted 3 months and infected over 100 people was reported in Kasese District, Uganda, where multiple cholera outbreaks had occurred previously. We conducted an investigation to identify the mode of transmission to guide control measures. Methods We defined a suspected case as onset of acute watery diarrhoea from 1 February 2015 onwards in a Kasese resident. A confirmed case was a suspected case with Vibrio cholerae O1 El Tor, serotype Inaba cultured from a stool sample. We reviewed medical records to find cases. We conducted a case-control study to compare exposures among confirmed case-persons and asymptomatic controls, matched by village and age-group. We conducted environmental assessments. We tested water samples from the most affected area for total coliforms using the Most Probable Number (MPN) method. Results We identified 183 suspected cases including 61 confirmed cases of Vibrio cholerae 01; serotype Inaba, with onset between February and July 2015. 2 case-persons died of cholera. The outbreak occurred in 80 villages and affected all age groups; the highest attack rate occurred in the 5–14 year age group (4.1/10,000). The outbreak started in Bwera Sub-County bordering the Democratic Republic of Congo and spread eastward through sustained community transmission. The first case-persons were involved in cross-border trading. The case-control study, which involved 49 confirmed cases and 201 controls, showed that 94% (46/49) of case-persons compared with 79% (160/201) of control-persons drank water without boiling or treatment (ORM-H=4.8, 95% CI: 1.3–18). Water collected from the two main sources, i.e., public pipes (consumed by 39% of case-persons and 38% of control-persons) or streams (consumed by 29% of case-persons and 24% control-persons) had high coliform counts, a marker of faecal contamination. Environmental assessment revealed evidence of open defecation along the streams. No food items were significantly associated with illness. Conclusions This prolonged, community-wide cholera outbreak was associated with drinking water contaminated by faecal matter and cross-border trading. We recommended rigorous disposal of patients’ faeces, chlorination of piped water, and boiling or treatment of drinking water. The outbreak stopped 6 weeks after these recommendations were implemented.

Background On 6 February 2015, Kampala city authorities alerted the Ugandan Ministry of Health of a “strange disease” that killed one person and sickened dozens. We conducted an epidemiologic investigation to identify the nature of the disease, mode of transmission, and risk factors to inform timely and effective control measures. Methods We defined a suspected case as onset of fever (≥37.5 °C) for more than 3 days with abdominal pain, headache, negative malaria test or failed anti-malaria treatment, and at least 2 of the following: diarrhea, nausea or vomiting, constipation, fatigue. A probable case was defined as a suspected case with a positive TUBEX® TF test. A confirmed case had blood culture yielding Salmonella Typhi. We conducted a case-control study to compare exposures of 33 suspected case-patients and 78 controls, and tested water and juice samples. Results From 17 February–12 June, we identified 10,230 suspected, 1038 probable, and 51 confirmed cases. Approximately 22.58% (7/31) of case-patients and 2.56% (2/78) of controls drank water sold in small plastic bags (ORM-H = 8.90; 95%CI = 1.60–49.00); 54.54% (18/33) of case-patients and 19.23% (15/78) of controls consumed locally-made drinks (ORM-H = 4.60; 95%CI: 1.90–11.00). All isolates were susceptible to ciprofloxacin and ceftriaxone. Water and juice samples exhibited evidence of fecal contamination. Conclusion Contaminated water and street-vended beverages were likely vehicles of this outbreak. At our recommendation authorities closed unsafe water sources and supplied safe water to affected areas.

Background A cholera outbreak started on 29 February in Bwikhonge Sub-county, Bulambuli District in Eastern Uganda. Local public health authorities implemented initial control measures. However, in late March, cases sharply increased in Bwikhonge Sub-county. We investigated the outbreak to determine its scope and mode of transmission, and to inform control measures. Methods We defined a suspected case as sudden onset of watery diarrhea from 1 March 2016 onwards in a resident of Bulambuli District. A confirmed case was a suspected case with positive stool culture for V. cholerae. We conducted descriptive epidemiologic analysis of the cases to inform the hypothesis on mode of transmission. To test the hypothesis, we conducted a case-control study involving 100 suspected case-patients and 100 asymptomatic controls, individually-matched by residence village and age. We collected seven water samples for laboratory testing. Results We identified 108 suspected cases (attack rate: 1.3%, 108/8404), including 7 confirmed cases. The case-control study revealed that 78% (78/100) of case-patients compared with 51% (51/100) of control-persons usually collected drinking water from the nearby Cheptui River (ORMH = 7.8, 95% CI = 2.7–22); conversely, 35% (35/100) of case-patients compared with 54% (54/100) of control-persons usually collected drinking water from borehole pumps (ORMH = 0.31, 95% CI = 0.13–0.65). The index case in Bwikhonge Sub-county had onset on 29 February but the outbreak had been on-going in the neighbouring sub-counties in the previous 3 months. V. cholera was isolated in 2 of the 7 river water samples collected from different locations. Conclusions We concluded that this cholera outbreak was caused by drinking contaminated water from Cheptui River. We recommended boiling and/or treating drinking water, improved sanitation, distribution of chlorine tablets to the affected villages, and as a long-term solution, construction of more borehole pumps. After implementing preventive measures, the number of cases declined and completely stopped after 6th April.

Introduction In October 2017, a blood sample from a resident of Kween District, Eastern Uganda, tested positive for Marburg virus. Within 24 hour of confirmation, a rapid outbreak response was initiated. Here, we present results of epidemiological and laboratory investigations. Methods A district task force was activated consisting of specialised teams to conduct case finding, case management and isolation, contact listing and follow up, sample collection and testing, and community engagement. An ecological investigation was also carried out to identify the potential source of infection. Virus isolation and Next Generation sequencing were performed to identify the strain of Marburg virus. Results Seventy individuals (34 MVD suspected cases and 36 close contacts of confirmed cases) were epidemiologically investigated, with blood samples tested for MVD. Only four cases met the MVD case definition; one was categorized as a probable case while the other three were confirmed cases. A total of 299 contacts were identified; during follow- up, two were confirmed as MVD. Of the four confirmed and probable MVD cases, three died, yielding a case fatality rate of 75%. All four cases belonged to a single family and 50% (2/4) of the MVD cases were female. All confirmed cases had clinical symptoms of fever, vomiting, abdominal pain and bleeding from body orifices. Viral sequences indicated that the Marburg virus strain responsible for this outbreak was closely related to virus strains previously shown to be circulating in Uganda. Conclusion This outbreak of MVD occurred as a family cluster with no additional transmission outside of the four related cases. Rapid case detection, prompt laboratory testing at the Uganda National VHF Reference Laboratory and presence of pre-trained, well-prepared national and district rapid response teams facilitated the containment and control of this outbreak within one month, preventing nationwide and global transmission of the disease., Author summary Marburg virus disease (MVD) is caused by the virus that belongs to the same family as that of Ebola Virus disease. The disease is characterized by severe clinical symptoms such as high fever, diarrhoea and vomiting, and severe bleeding from most body openings. On average, 54% of the people who get infected with Marburg virus die from it [1]. In October 2017, Uganda reported an outbreak of MVD in the eastern district of Kween that borders Kenya in the Mount Elgon plains. This was the first time MVD was being detected in this part of the country since previous MVD outbreaks had been reported in the western part of Uganda. The Ministry of Health together with partners instituted rapid outbreak response for control. Investigations revealed a cluster of one family involving four cases whereby only one survived. The outbreak was traced back into bat caves in Kween district. Rock salt mining in the cave led to a spill-over of the virus into the human population with the subsequent person-to-person transmission. Through contact tracing and isolation of the infected people among other approaches, the outbreak was brought under control as explained in this article.

Introduction Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne, zoonotic viral disease that causes haemorrhagic symptoms. Despite having eight confirmed outbreaks between 2013 and 2017, all within Uganda’s ‘cattle corridor’, no targeted tick control programs exist in Uganda to prevent disease. During a seven-month-period from July 2018-January 2019, the Ministry of Health confirmed multiple independent CCHF outbreaks. We investigated to identify risk factors and recommend interventions to prevent future outbreaks. Methods We defined a confirmed case as sudden onset of fever (≥37.5°C) with ≥4 of the following signs and symptoms: anorexia, vomiting, diarrhoea, headache, abdominal pain, joint pain, or sudden unexplained bleeding in a resident of the affected districts who tested positive for Crimean-Congo haemorrhagic fever virus (CCHFv) by RT-PCR from 1 July 2018–30 January 2019. We reviewed medical records and performed active case-finding. We conducted a case-control study and compared exposures of case-patients with age-, sex-, and sub-county-matched control-persons (1:4). Results We identified 14 confirmed cases (64% males) with five deaths (case-fatality rate: 36%) from 11 districts in western and central region. Of these, eight (73%) case-patients resided in Uganda’s ‘cattle corridor’. One outbreak involved two case-patients and the remainder involved one. All case-patients had fever and 93% had unexplained bleeding. Case-patients were aged 6–36 years, with persons aged 20–44 years more affected (AR: 7.2/1,000,000) than persons ≤19 years (2.0/1,000,000), p = 0.015. Most (93%) case-patients had contact with livestock ≤2 weeks before symptom onset. Twelve (86%) lived, Author summary Uganda has had multiple Crimean-Congo haemorrhagic fever outbreaks since 2013 when the first outbreak was confirmed. Tick exposure has been identified as the major risk factor by our study and this finding was similar with other studies done during outbreaks in Uganda. However, Uganda still lacks national tick control guidelines and indiscriminate use of acaricides (pesticides specially for ticks) has been observed widely. This has been cited to influence increased tick resistance to acaricides. Our study might not indicate whether tick resistance to acaricides has increased tick populations in Uganda however it is imperative that tick control is considered in efforts of prevention and control of CCHF outbreaks. We therefore recommend improved tick control in Uganda through national regulations on acaricide distribution and use, development of strategies to reduce tick resistance to acaricides in the country, and more community-based engagement of tick control in livestock management.

Background On 28 March, 2016, the Ministry of Health received a report on three deaths from an unknown disease characterized by fever, jaundice, and hemorrhage which occurred within a one-month period in the same family in central Uganda. We started an investigation to determine its nature and scope, identify risk factors, and to recommend eventually control measures for future prevention. Methods We defined a probable case as onset of unexplained fever plus ≥1 of the following unexplained symptoms: jaundice, unexplained bleeding, or liver function abnormalities. A confirmed case was a probable case with IgM or PCR positivity for yellow fever. We reviewed medical records and conducted active community case-finding. In a case-control study, we compared risk factors between case-patients and asymptomatic control-persons, frequency-matched by age, sex, and village. We used multivariate conditional logistic regression to evaluate risk factors. We also conducted entomological studies and environmental assessments. Results From February to May, we identified 42 case-persons (35 probable and seven confirmed), of whom 14 (33%) died. The attack rate (AR) was 2.6/100,000 for all affected districts, and highest in Masaka District (AR = 6.0/100,000). Men (AR = 4.0/100,000) were more affected than women (AR = 1.1/100,000) (p = 0.00016). Persons aged 30–39 years (AR = 14/100,000) were the most affected. Only 32 case-patients and 128 controls were used in the case control study. Twenty three case-persons (72%) and 32 control-persons (25%) farmed in swampy areas (ORadj = 7.5; 95%CI = 2.3–24); 20 case-patients (63%) and 32 control-persons (25%) who farmed reported presence of monkeys in agriculture fields (ORadj = 3.1, 95%CI = 1.1–8.6); and 20 case-patients (63%) and 35 control-persons (27%) farmed in forest areas (ORadj = 3.2; 95%CI = 0.93–11). No study participants reported yellow fever vaccination. Sylvatic monkeys and Aedes mosquitoes were identified in the nearby forest areas. Conclusion This yellow fever outbreak was likely sylvatic and transmitted to a susceptible population probably by mosquito bites during farming in forest and swampy areas. A reactive vaccination campaign was conducted in the affected districts after the outbreak. We recommended introduction of yellow fever vaccine into the routine Uganda National Expanded Program on Immunization and enhanced yellow fever surveillance.

Background On 12 October, 2016 a measles outbreak was reported in Mayuge District, eastern Uganda. We investigated the outbreak to determine its scope, identify risk factors for transmission, evaluate vaccination coverage and vaccine effectiveness, and recommend evidence-based control measures. Methods We defined a probable case as onset of fever (≥3 days) and generalized rash, plus ≥1 of the following: conjunctivitis, cough, and/or runny nose in a Mayuge District resident. A confirmed case was a probable case with measles-specific IgM (+) not explained by vaccination. We reviewed medical records and conducted active community case-finding. In a case-control investigation involving probable case-persons and controls matched by age and village, we evaluated risk factors for transmission for both cases and controls during the case-person’s likely exposure period (i.e., 7–21 days prior to rash onset). We estimated vaccine effectiveness (VE) using the formula: VE ≈ (1-ORprotective) × 100. We calculated vaccination coverage using the percentage of controls vaccinated. Results We identified 62 probable case-persons (attack rate [AR] = 4.0/10,000), including 3 confirmed. Of all age groups, children

Globally, even though improvements have been made to effective surveillance and response, communicable diseases such as cholera remain high priorities for national health programs, especially in Africa. High-quality surveillance information coupled with adequate laboratory facilities are effective in curbing outbreaks from such diseases, ultimately reducing morbidity and mortality. One way of building this capacity is through simulation of response to such health events. This case study based on a cholera outbreak investigated by FETP trainees in October 2015 in Uganda can be used to reinforce skills of frontline FETP trainees and other novice public health practitioners through a practical simulation approach. This activity should be completed in 2.5 hours.

Background In April 2015, Kamwenge District, western Uganda reported a measles outbreak. We investigated the outbreak to identify potential exposures that facilitated measles transmission, assess vaccine effectiveness (VE) and vaccination coverage (VC), and recommend prevention and control measures. Methods For this investigation, a probable case was defined as onset of fever and generalized maculopapular rash, plus ≥1 of the following symptoms: Coryza, conjunctivitis, or cough. A confirmed case was defined as a probable case plus identification of measles-specific IgM in serum. For case-finding, we reviewed patients’ medical records and conducted in-home patient examination. In a case-control study, we compared exposures of case-patients and controls matched by age and village of residence. For children aged 9 m-5y, we estimated VC using the percent of children among the controls who had been vaccinated against measles, and calculated VE using the formula, VE = 1 - ORM-H, where ORM-H was the Mantel-Haenszel odds ratio associated with having a measles vaccination history. Results We identified 213 probable cases with onset between April and August, 2015. Of 23 blood specimens collected, 78% were positive for measles-specific IgM. Measles attack rate was highest in the youngest age-group, 0-5y (13/10,000), and decreased as age increased. The epidemic curve indicated sustained propagation in the community. Of the 50 case-patients and 200 controls, 42% of case-patients and 12% of controls visited health centers during their likely exposure period (ORM-H = 6.1; 95% CI = 2.7–14). Among children aged 9 m-5y, VE was estimated at 70% (95% CI: 24–88%), and VC at 75% (95% CI: 67–83%). Excessive crowding was observed at all health centers; no patient triage-system existed. Conclusions The spread of measles during this outbreak was facilitated by patient mixing at crowded health centers, suboptimal VE and inadequate VC. We recommended emergency immunization campaign targeting children

Globalization has opened many fronts for disease outbreaks because of the quick movement of people and porous borders around the world. The emergence of zoonotic diseases and other communicable diseases highlights the need for implementation of the Global Health Security Agenda packages if countries are to achieve compliance with International Health Regulations (IHR 2005). Health workforce development is one of the critical components that must be addressed with utmost urgency if gaps in early disease detection and response are to be addressed. In this regard, this case study is based on a measles outbreak investigation in Uganda simulating a real-life outbreak investigation by field epidemiologists and seeks to demonstrate the principles of applied epidemiology outlining the critical steps in outbreak investigations and generation of evidence for decision making. It aims to shore up the health workforce capacity by providing practical training for field epidemiology students and professionals that builds their skills in outbreak investigation. This case study can be completed in less than three hours.

Introduction : on March 28, 2016 a cluster of deaths resulting from jaundice and hemorrhagic symptoms occurred in Masaka, Central Uganda. We investigated this outbreak to determine the nature of disease, identify risk factors, and recommend control and prevention measures. Methods : we defined a suspected case-person as onset in residents of Masaka, Rukungiri and Kalangala districts from January 2016 onwards of fever not responding to malaria treatment, plus ≥2 of the following: abdominal pain/diarrhea, headache, jaundice, unexplained bleeding. A confirmed case was a suspected case with positive IgM or PCR tests for yellow fever. We conducted medical record reviews and active community case-finding. In a case-control study we compared potential exposures between 32 case-persons and 128 asymptomatic controls matched by age, sex and village. We also conducted entomological studies and environmental assessments. Results : we identified 32 cases (7 confirmed). The overall attack rate (AR, per 100,000) was 0.48 overall (6.4 Masaka, 3.1 Rukungiri and 1.9 Kalangala); the case-fatality rate was 22% (7/32). Men (AR=1.2/10,000) and persons aged 30-39 years (AR = 4.0/10,000) were most affected. 20 (63%) of 32 case-persons and 35 (27%) of 128 control-persons cultivated in forest areas (ORM-H=4.3; 95%CI=1.9-9.7); 23 (71%) of 32 case-persons and 32 (25%) 128 control-persons cultivate in swampy areas (ORM-H=7.5; 95%CI=2.0-18). No one interviewed during this investigation was vaccinated against yellow fever. Sylvatic monkeys and Aedes mosquitoes were identified in the nearby forest areas. Conclusion : this was a sylvatic yellow fever outbreak that occurred in a susceptible population, likely transmitted by mosquito bites during cultivation in forest and swampy areas. We recommended yellow fever vaccination in affected districts and enhanced yellow fever surveillance in neighboring districts. The outbreak stopped following the vaccination.

Introduction : on 17th September 2015, the Ugandan Ministry of Health received reports from Buliisa District about mysterious death of people. The predominant symptom was hematemesis (vomiting of blood). By September 24, 2015, there had been 4 deaths. We investigated to verify existence of an outbreak, determine mode of disease transmission, and identify risk factors. Methods : we conducted a community-based active case-finding in Hoima and Buliisa districts, Western Uganda between 3 and 17 October 2015. A suspected case was defined as a resident of Hoima, Buliisa or neighbouring districts who had onset of hematemesis between 1 June 2015 and 15 October 2015. A control was an individual without any history of hematemesis. Biological specimens were collected from 19 cases and tested for viral haemorrhagic fevers (VHFs), including Ebola, Marburg, Crimean-Congo Haemorrhagic Fever and Rift Valley Fever viruses. Histopathology and bacterial examinations were also conducted. In a case-control study, we compared exposures of 21 cases and 81 controls. We used Mantel-Haenszel method to estimate odds ratios (OR) associated with exposures.

Introduction : in September 2015, a cholera outbreak occurred in a village in Hoima District, western Uganda. The Ministry of Health assembled a rapid response team, with support by CDC, UNICEF and WHO, to investigate the outbreak, establish the Kaiso Cholera Treatment Center (KCTC), and implement control measures. The team identified 120 cholera cases (with 5 deaths) and determined that drinking contaminated water from the lakeshore caused this outbreak. We sought to determine the cost of investigating and controlling this outbreak, and compare it to a would-be simple preventive measure, constructing deep wells to provide cleaner water. Methods : we collected cost data, including personnel and material costs at KCTC, health facilities, Hoima District Health Office, Uganda Public Health Fellowship Program, UNICEF, CDC, and WHO. We defined direct cost of responding to this outbreak as expenditure on medications, medical equipment and supplies, utilities, and allowances and transport for responders; indirect cost included salary and other compensations for responders. We did not include difficult-to-measure costs such as vehicle depreciation, building maintenance, and loss of productivity to case-persons due to illness and deaths. The cost of constructing deep wells was quoted by a U.S.-based NGO. Results : the total cost incurred in investigating and controlling this outbreak was $71,769, including $21,059 in direct cost ($19,225 for allowances and transportation, $1,774 for medical equipment and supplies, and $60 for utilities), and $50,620 in indirect cost (74,484 person-hours of salary and other compensations for responders). Conversely, constructing a deep well to provide cleaner water would cost approximately $2500. Essentially, the total cost incurred in this outbreak would have been enough to construct 28 (=71769/2500) deep wells; even the direct cost only would have been enough to construct 8 (=21059/2500) deep wells. One such deep well would have prevented this outbreak and averted future waterborne outbreaks. Conclusion : a simple prevention measure such as constructing deep wells for village residents can be substantially cost-effective for preventing waterborne diseases such as cholera. We recommend that the government should proactively implement prevention measures for waterborne outbreaks whenever possible, instead of passively responding to these outbreaks.

In June 2015, the District Health Officer of Kasese District, southwestern Uganda reported an outbreak of cholera in a fishing village. Two fellows of the Uganda Public Health Fellowship Program – Field Epidemiology Track conducted an investigation to verify the existence of an outbreak, determine the mode of transmission, and recommend control measures. This case study describes that investigation, which teaches the steps in an outbreak investigation and the details in each step, what needs to be done in each step to achieve the objectives of the investigation, and what might be the common pitfalls during an outbreak investigation. This case study can be used to teach the fundamental principles of an outbreak investigation and use of Epi Info for outbreak analysis. The audience are field epidemiologists at various levels in different settings.

Introduction : Bulambuli District, eastern Uganda experienced a cholera outbreak since January, 2016. Generic control measures implemented by the local public health authorities failed to contain the outbreak. In late-March, a sharp increase in the number of cases occurred in Bwikhonge Sub-county. We conducted an investigation to determine the scope of the outbreak, mode of transmission, and to inform control interventions. Methods : we defined a suspected case as sudden onset of watery diarrhea from 1 March 2016 onwards in a resident of Bulambuli District. A confirmed case was a suspected case with positive stool culture for V. Cholerae. We conducted active case-finding, performed descriptive epidemiologic analysis, and interviewed 40 suspected case-patients for hypothesis generation. We conducted a case-control study in which we interviewed 100 case-patients and 100 asymptomatic controls, matched by village of residence and age. We also conducted an environmental assessment. Results : we identified 108 suspected cases (attack rate: 1.3%, 108/8404), 8 of which were confirmed cases. Low-level transmission occurred between 2 and 21 March. Cases sharply increased on 24 March, followed by a six-day plateau and a rapid decline after 30th March, indicating a continuous common-source outbreak. The case-control study showed that 76% (76/100) of case-patients versus 54% (54/100) of control-persons usually collected drinking water from the nearby Cheptui River (ORMH=7.8, 95%CI=2.7-23); conversely, 36% (35/98) of case-patients and 54% (54/100) of control-persons usually collected drinking water from boreholes (ORMH=0.30, 95%CI=0.13-0.65). A case-patient with onset on 22 March defecated near the water-collection point in the river; subsequently, many case-patients washed their soiled clothes at the drinking-water collection point. Vibrio cholera 01 Ogawa was isolated in 2 of the 7 river water samples. Conclusion : this cholera outbreak was caused by drinking water from Cheptui River contaminated by a patient’s feces initially and washing of soiled clothes subsequently. We recommended health education on boiling and/or treating water, restriction on washing clothes near river water collection points, improved sanitation, and distributing chlorine tablets to the affected villages, and, as a long-term solution, construction of more boreholes. After implementing our recommendations, cases declined and completely stopped after 6 April.

Introduction : on 15 March 2016, Namayingo District reported a cholera outbreak in three locations, with four confirmed cases. We investigated to identify mode of transmission and recommend evidence-based control measures.

Introduction: On 17 September 2015, Buliisa District Health Office reported multiple deaths due to haemorrhage to the Uganda Ministry of Health. We conducted an investigation to verify the existence of an outbreak and to identify the disease nature, mode of transmission and risk factors. Methods: We defined a suspected case as onset of hematemesis between 1 June 2015 and 15 October 2015 in a resident of Hoima, Buliisa or neighbouring districts. We identified cases by reviewing medical records and actively searching in the community. We interviewed casepatients and health-care workers and performed descriptive epidemiology to generate hypotheses on possible exposures. In a case-control study we compared exposures between 21 cases and 81 controls, matched by age (± 10 years), sex and village of residence. We collected 22 biological specimens from 19 case-patients to test for Viral Haemorrhagic Fevers (VHF). We analysed the data using the Mantel-Haenszel method to account for the matched study design. Results: We identified 56 cases with onset from June to October (attack rate 15/100,000 in Buliisa District and 5.2/100,000 in Hoima District). The age-specific attack rate was highest in persons aged 31-60 years (15/100,000 in Hoima and 47/100,000 in Buliisa); no persons below 15 years of age had the illness. In the case-control study, 42% (5/12) of cases vs. 0.0% (0/77) of controls had liver disease (ORM-H = ∞; 95%CI = 3.7-∞); 71% (10/14) of cases vs. 35% (28/81) of controls had ulcer disease (ORM-H = 13; 95% CI = 1.6-98); 27% (3/11) of cases vs. 14% (11/81) of controls used indomethacin prior to disease onset (ORM-H = 6.0; 95% CI = 1.0-36). None of the blood samples were positive for any of the VHFs. Conclusion: This reported cluster of hematemesis illness was due to predisposing conditions and use of Non- Steroidal Anti-inflammatory Drugs (NSAID). Health education should be conducted on the danger of NSAIDs misuse, especially in persons with predisposing conditions. Keywords: Hematemesis, outbreak, case-control, Uganda

Background Between January and June, 2015, a large typhoid fever outbreak occurred in Kampala, Uganda, with 10,230 suspected cases. During the outbreak, area surgeons reported a surge in cases of typhoid intestinal perforation (TIP), a complication of typhoid fever. We conducted an investigation to characterize TIP cases and identify modifiable risk factors for TIP. Methods We defined a TIP case as a physician-diagnosed typhoid patient with non-traumatic terminal ileum perforation. We identified cases by reviewing medical records at all five major hospitals in Kampala from 2013 to 2015. In a matched case-control study, we compared potential risk factors among TIP cases and controls; controls were typhoid patients diagnosed by TUBEX TF, culture, or physician but without TIP, identified from the outbreak line-list and matched to cases by age, sex and residence. Cases and controls were interviewed using a standard questionnaire from 1st -23rd December 2015. We used conditional logistic regression to assess risk factors for TIP and control for confounding. Results Of the 88 TIP cases identified during 2013–2015, 77% (68/88) occurred between January and June, 2015; TIPs sharply increased in January and peaked in March, coincident with the typhoid outbreak. The estimated risk of TIP was 6.6 per 1000 suspected typhoid infections (68/10,230). The case-fatality rate was 10% (7/68). Cases sought care later than controls; Compared with 29% (13/45) of TIP cases and 63% (86/137) of controls who sought treatment within 3 days of onset, 42% (19/45) of cases and 32% (44/137) of controls sought treatment 4–9 days after illness onset (ORadj = 2.2, 95%CI = 0.83–5.8), while 29% (13/45) of cases and 5.1% (7/137) of controls sought treatment ≥10 days after onset (ORadj = 11, 95%CI = 1.9–61). 68% (96/141) of cases and 23% (23/100) of controls had got treatment before being treated at the treatment centre (ORadj = 9.0, 95%CI = 1.1–78). Conclusion Delay in seeking treatment increased the risk of TIPs. For future outbreaks, we recommended aggressive community case-finding, and informational campaigns in affected communities and among local healthcare providers to increase awareness of the need for early and appropriate treatment.

In 2013, an oropharyngeal tularemia outbreak in Turkey affected 55 persons. Drinking tap water during the likely exposure period was significantly associated with illness (attack rate 27% vs. 11% among non-tap water drinkers). Findings showed the tap water source had been contaminated by surface water, and the chlorination device malfunctioned.

Background In February 2009, a high school student was diagnosed with sputum-smear positive pulmonary tuberculosis (TB). One year later, 2 other students in the same grade developed sputum-smear positive TB. Methods We used tuberculin skin testing (TST), chest radiography, sputum smear, and symptomatology for case identification. We defined latent TB infection (LTBI) as a TST induration of 15 mm or larger, probable TB as a chest radiograph indicative of TB plus productive cough/hemoptysis for at least 2 weeks or TST induration of 15 mm or larger, and confirmed TB as 2 or more positive sputum smears or 1 positive sputum smear plus a chest radiograph indicative of TB. Results Of students in the same grade as the primary case-student, 26% (122/476) had LTBI and 4.8% (23/476) had probable/confirmed TB. Of teachers, 43% (18/42) had LTBI and none had probable/confirmed TB. Sharing a classroom with the primary case-student increased risk for LTBI (rate ratio = 2.5; 95% CI: 1.9–3.4) and probable/confirmed TB (rate ratio = 17, 95% CI: 7.8–39). Of students with LTBI in February 2009 who refused prophylaxis, 50% (11/22) had probable/confirmed TB in April 2010. Conclusions This TB outbreak was likely started by delayed diagnosis of TB in the case-student and was facilitated by lack of post-exposure chemoprophylaxis. Post-exposure prophylaxis is strongly recommended for all TST-positive students.

On 20 June 2015, a cholera outbreak affecting more than 30 people was reported in a fishing village, Katwe, in Kasese District, south-western Uganda. We investigated this outbreak to identify the mode of transmission and to recommend control measures. We defined a suspected case as onset of acute watery diarrhoea between 1 June and 15 July 2015 in a resident of Katwe village; a confirmed case was a suspected case with Vibrio cholerae cultured from stool. For case finding, we reviewed medical records and actively searched for cases in the community. In a case-control investigation we compared exposure histories of 32 suspected case-persons and 128 age-matched controls. We also conducted an environmental assessment on how the exposures had occurred. We found 61 suspected cases (attack rate = 4.9/1000) during this outbreak, of which eight were confirmed. The primary case-person had onset on 16 June; afterwards cases sharply increased, peaked on 19 June, and rapidly declined afterwards. After 22 June, eight scattered cases occurred. The case-control investigation showed that 97% (31/32) of cases and 62% (79/128) of controls usually collected water from inside a water-collection site "X" (ORM-H = 16; 95% CI = 2.4-107). The primary case-person who developed symptoms while fishing, reportedly came ashore in the early morning hours on 17 June, and defecated "near" water-collection site X. We concluded that this cholera outbreak was caused by drinking lake water collected from inside the lakeshore water-collection site X. At our recommendations, the village administration provided water chlorination tablets to the villagers, issued water boiling advisory to the villagers, rigorously disinfected all patients' faeces and, three weeks later, fixed the tap-water system.

BACKGROUND Human enterovirus 71 (HEV71) causes outbreaks of life-threatening diseases throughout the world. The genesis of these severe diseases is unknown. METHODS During an outbreak of HEV71 infection, we investigated risk factors for critical illness. We developed a modified pediatric index of mortality (mPIM) incorporating heart rate, temperature, white blood cell count, respiratory rate, chest infiltrates, skin color, reflexes, responsiveness, and mobility. We calculated the mPIM for 103 patients (22 deaths) using complete scoring criteria in the medical record. In a case-control study, we compared cases (mPIM > or =10 or death) with controls (mPIM = 0-9) by drugs received within 96 hours after onset of fever, initial temperature, age, and nutritional anthropometry. RESULTS About 66% (68/103) of the patients with an mPIM score (28 cases and 40 controls) had data on initial exposures. About 50% of the 28 cases and 18% of the 40 controls received an injection to treat fever during the first 96 hours after onset (Odds ratio [OR] = 7.0, 95% confidence interval [CI]: 1.8-28). Injections containing exclusively glucocorticoids (OR = 4.8, 95% CI: 1.2-21) or pyrazolones (OR = 4.1, 95% CI: 0.91-19, P = 0.047) were risk factors for severe HEV71 infection. About 25% of cases and 5% of controls received both drugs parenterally while 7% of cases and 30% of controls received neither (OR = 21, 95% CI: 1.8-305). Conversely, cases and controls had identical average initial temperature, and did not differ significantly by age, sex, nutritional measurements, use of other drugs, or timeliness of medical care received. CONCLUSION Fever treatment with glucocorticoids and/or pyrazolones is a risk factor for life-threatening HEV71 infection.

Shigellosis outbreaks in daycare centers result in substantial disease and economic burdens in the United States. The emergence of multidrug resistant Shigella strains raises questions regarding control of transmission within daycare centers and treatment for children. From May to October 2005, 639 Shigella sonnei cases were reported in northwest Missouri, mostly among persons exposed to daycare centers.We conducted a case-control investigation among licensed daycare centers (LDCs) in northwest Missouri to determine transmission risk factors, tested isolates for antimicrobial resistance, and described treatment practices. Case LDCs had secondary attack rates of shigellosisor=2% (range, 2%-25%) and control LDCsor=2% (range, 0%-1.3%). We interviewed LDC staff and performed on-site inspections. Thirty-one outbreak isolates were tested for antimicrobial resistance. We interviewed physicians and reviewed health department outbreak-related treatment data.We enrolled 18 case and 21 control LDCs. LDCs withor=1 sink in every room (odds ratio [OR]: 0.1; 95% confidence interval [CI]: 0.02-0.5) or a diapering station in every room (OR: 0.1; 95% CI: 0.01-0.6) were less likely to be case-LDCs. Resistance to ampicillin and trimethoprim-sulfamethoxazole was found in 90% of the outbreak strains. Among 210 children treated with antimicrobial agents, azithromycin was used in 92 (44%) while a fluoroquinolone was used in 11 (5%) children.During a large daycare center-associated shigellosis outbreak, strains were highly resistant to ampicillin and trimethoprim-sulfamethoxazole. Children were frequently treated with azithromycin and occasionally fluoroquinolones. Appropriate handwashing and diapering infrastructure are necessary to minimize spread of shigellosis within daycare centers, and could reduce use of antimicrobial agents.

Background: Between September and December 2003, an outbreak of pertussis occurred in Cass County, MO, mostly among adolescent school children. Methods: We conducted a 1:2 matched case-control study among school children and used conditional logistic regression to evaluate risk factors for pertussis, including the total number of vaccine doses received, age at administration of each dose of vaccine and the type of vaccine (whole cell or acellular). Results: Of all 127 pertussis cases reported in this outbreak, the majority were adolescents (10-19 years of age, 50%) and adults (20 years or older, 22%); only 10% were infants and children less than 5 years of age. Because the focus of our investigation was on school-aged children, we enrolled 237 students (79 cases and 158 controls) in our study. Students missing at least one dose of the vaccine had higher risk for pertussis than those who received all 5 doses (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.17-4.77). Early administration of the fifth dose of the vaccine at age 4 years was significantly associated with risk for pertussis compared with vaccination at age 5 years (adjusted OR, 2.45; 95% CI, 1.16-5.16). A short time interval (

Improving personal hygienic practices may prevent and control MRSA outbreaks., Methicillin-resistant Staphylococcus aureus (MRSA) infections outside the healthcare setting are an increasing concern. We conducted a case-control study to investigate an MRSA outbreak during 2002–2003 in a Missouri prison and focused on hygiene factors. Information on sociodemographic characteristics, medical history, and hygiene practices of study participants was collected by interview and medical record review. Logistic regression was used to evaluate MRSA infection in relation to hygiene factors individually and as a composite hygiene score; potential confounding factors were controlled. Selected MRSA isolates were analyzed by pulsed-field gel electrophoresis (PFGE). MRSA infection was significantly associated with a low composite hygiene score. Transmission among prison inmates appeared to be responsible for this outbreak. PFGE analysis showed that isolates were indistinguishable and associated with community-onset MRSA infections in other US prisons. Improving hygiene practices and environmental conditions may help prevent and interrupt future MRSA outbreaks in prison settings.

Background On 6 February 2015, Kampala city authorities alerted the Ugandan Ministry of Health of a “strange disease” that killed one person and sickened dozens. We conducted an epidemiologic investigation to identify the nature of the disease, mode of transmission, and risk factors to inform timely and effective control measures. Methods We defined a suspected case as onset of fever (≥37.5 °C) for more than 3 days with abdominal pain, headache, negative malaria test or failed anti-malaria treatment, and at least 2 of the following: diarrhea, nausea or vomiting, constipation, fatigue. A probable case was defined as a suspected case with a positive TUBEX® TF test. A confirmed case had blood culture yielding Salmonella Typhi. We conducted a case-control study to compare exposures of 33 suspected case-patients and 78 controls, and tested water and juice samples. Results From 17 February–12 June, we identified 10,230 suspected, 1038 probable, and 51 confirmed cases. Approximately 22.58% (7/31) of case-patients and 2.56% (2/78) of controls drank water sold in small plastic bags (ORM-H = 8.90; 95%CI = 1.60–49.00); 54.54% (18/33) of case-patients and 19.23% (15/78) of controls consumed locally-made drinks (ORM-H = 4.60; 95%CI: 1.90–11.00). All isolates were susceptible to ciprofloxacin and ceftriaxone. Water and juice samples exhibited evidence of fecal contamination. Conclusion Contaminated water and street-vended beverages were likely vehicles of this outbreak. At our recommendation authorities closed unsafe water sources and supplied safe water to affected areas. Electronic supplementary material The online version of this article (doi:10.1186/s12889-016-4002-0) contains supplementary material, which is available to authorized users.