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The global Guinea worm eradication program represents one of the great public health success stories of our time. Since the program’s inception in 1980, the number of annual human cases has reduced by 99.9%, from an estimated 3.5 million cases in 21 countries1 to only 54 cases in three countries at the end of 2019.2,3 Causing significant disability and pain, Guinea worm infection occurs through the ingestion of freshwater copepods (small water crustaceans) infected with stage 3 Dracunculus medinensis larvae. After approximately 10–14 months, a blister forms (usually on a lower limb) where the pregnant adult female Guinea worm ruptures the skin.4 Upon detection of a possible Guinea worm case, patients are transported to health centers where they receive care. The worm is extracted via “controlled immersion,” in which the wound is submerged in a water-filled container to induce worm emergence without the risk of contaminating public water sources.5 Guinea worm is a disease of poverty, primarily impacting people in remote areas who do not have access to safe water for drinking and are forced to drink from stagnant water sources such as ponds, pools, and unprotected open wells that may contain infected copepods.5 The seasonality of disease incidence varies geographically owing to the timing of precipitation patterns and abundance of stagnant water sources.5 For example, in the Sahel (Mali, Niger, Chad), cases historically peaked in the months May through October when stagnant water sources are most abundant. Young adults (15–45 years of age) are most likely to be infected with D. medinensis, although persons of all ages can develop infection.5 Guinea worm cases have historically been equally distributed among men and women, though some exceptions have been noted.5 Occupation is an important risk factor; farmers and persons who fetch drinking water are commonly infected.5 In some countries (i.e., Mali, Niger, and Burkina Faso), certain ethnic groups are at higher risk of infection because of seasonal migration across long distances and, in some cases, the seasonal search for water or pasture for cattle.5 Conventional thought about Guinea worm transmission ecology was challenged in 2012 when canine cases were first reported in Chad in significant numbers,6 spurring new research on transmission dynamics. Today, Chad is the epicenter of D. medinensis transmission, reporting 88% of human cases (N = 48) and virtually all canine cases (99%, N = 1,927) worldwide in 2019.2,3,7 Recent case-control studies conducted in Chad have shown that water sources associated with increased risk for Guinea worm include lagoons, ponds, and untreated water from hand-dug wells.8,9 No associations have been observed to date between human Guinea worm and consumption of fish and frogs,9 which has been demonstrated in dogs.10 This is could be because humans are less likely than dogs to consume uncooked small fish/fingerlings and frogs, which can serve as transport or paratenic hosts.11,12 Over five years have passed since Eberhard et al.6 first described the unusual epidemiological patterns in Chad, noting that human cases are sporadic and rare in comparison with canine cases, with no apparent association with common water sources and no clustering by village. Since that time, the number of canine cases has generally increased steadily as surveillance expanded,2,3,13 whereas human cases have remained generally constant and at low numbers.2,3 Here, we use additional surveillance data to determine whether those epidemiologic patterns persist and to characterize in greater depth human Guinea worm in Chad, with the broader goal of furthering our understanding D. medinensis transmission and epidemiology.

Increased levels of guinea worm (GW) disease transmission among dogs in villages along the Chari River in Chad threaten the gains made by the GW Eradication Program. Infected dogs with preemergent worm blisters are difficult to proactively identify. If these dogs are not contained, blisters can burst upon submersion in water, leading to the contamination of the water supply with L1 larvae. Guinea worm antigens previously identified using sera from human dracunculiasis patients were coupled to polystyrene beads for multiplex bead assay analysis of 41 non-endemic (presumed negative) dog sera and 39 sera from GW-positive dogs from Chad. Because commercially available anti-dog IgG secondary antibodies did not perform well in the multiplex assay, dog IgGs were partially purified, and a new anti-dog IgG monoclonal antibody was developed. Using the new 4E3D9 monoclonal secondary antibody, the thioredoxin-like protein 1-glutathione-S-transferase (GST), heat shock protein (HSP1)-GST, and HSP2-GST antigen multiplex assays had sensitivities of 69-74% and specificities of 73-83%. The domain of unknown function protein 148 (DUF148)-GST antigen multiplex assay had a sensitivity of 89.7% and a specificity of 85.4%. When testing samples collected within 1 year of GW emergence (n = 20), the DUF148-GST assay had a sensitivity of 90.0% and a specificity of 97.6% with a receiver-operating characteristic area under the curve of 0.94. Using sera from two experimentally infected dogs, antibodies to GW antigens were detected within 6 months of exposure. Our results suggest that, when used to analyze paired, longitudinal samples collected 1-2 months apart, the DUF148/GST multiplex assay could identify infected dogs 4-8 months before GW emergence.

Acanthamoeba keratitis (AK) is a painful, potentially blinding eye disease associated with contact lens use and corneal injury. AK, caused by the free-living amoeba Acanthamoeba, is ubiquitous in the environment and has been isolated from municipal water supplies. It can be tolerant of normal chlorine levels in drinking water. An AK outbreak investigated in 2003–2005 in five Illinois counties showed a lower AK age-standardized rate ratio in Cook County than in surrounding counties and was hypothesized to be due in part to reductions in residual disinfectant levels (RDLs) in drinking water. We evaluated RDLs in public water systems in the same five Illinois counties over eight years (2002–2009) using a multivariable model of water system RDL measurements. Fitted RDLs for each county were in the acceptable range by United States Environmental Protection Agency standards for the entire study period. After correcting for multiple testing, two of the surrounding counties had fitted RDLs that differed from Cook County for one year—this pattern differed from the epidemiologic pattern of cases observed in the AK outbreak. Our findings do not support the hypothesis that the development of AK was associated with changes in RDLs in the five Illinois counties.

Improved water quality reduces diarrhea, but the impact of improved water quality on Ascaris and Trichuris, soil-transmitted helminths (STH) conveyed by the fecal-oral route, is less well described. To assess water quality associations with diarrhea and STH, we conducted a cross-sectional survey in households of south-eastern Guatemala. Diarrhea was self-reported in the past week and month. STH was diagnosed by stool testing using a fecal parasite concentrator method. We explored associations between Escherichia coli-positive source water (water quality) and disease outcomes using survey logistic regression models. Overall, 732 persons lived in 167 households where water was tested. Of these, 79.4% (581/732) had E. coli-positive water, 7.9% (58/732) had diarrhea within the week, 14.1% (103/732) had diarrhea within the month, and 6.6% (36/545) tested positive for Ascaris or Trichuris, including 1% (6/536) who also reported diarrhea. Univariable analysis found a statistically significant association between water quality and STH (odds ratio [OR] = 5.1, 95% confidence interval [CI] = 1.1–24.5) but no association between water quality and diarrhea. Waterborne transmission and effects of water treatment on STH prevalence should be investigated further. If a causal relationship is found, practices such as household water treatment including filtration might be useful adjuncts to sanitation, hygiene, and deworming in STH control programs.

BACKGROUND During 2009 and 2010, 2 clusters of organ transplant-transmitted Balamuthia mandrillaris, a free-living ameba, were detected by recognition of severe unexpected illness in multiple recipients from the same donor. METHODS We investigated all recipients and the 2 donors through interview, medical record review, and testing of available specimens retrospectively. Surviving recipients were tested and treated prospectively. RESULTS In the 2009 cluster of illness, 2 kidney recipients were infected and 1 died. The donor had Balamuthia encephalitis confirmed on autopsy. In the 2010 cluster, the liver and kidney-pancreas recipients developed Balamuthia encephalitis and died. The donor had a clinical syndrome consistent with Balamuthia infection and serologic evidence of infection. In both clusters, the 2 asymptomatic recipients were treated expectantly and survived; 1 asymptomatic recipient in each cluster had serologic evidence of exposure that decreased over time. Both donors had been presumptively diagnosed with other neurologic diseases prior to organ procurement. CONCLUSIONS Balamuthia can be transmitted through organ transplantation with an observed incubation time of 17-24 days. Clinicians should be aware of Balamuthia as a cause of encephalitis with high rate of fatality, and should notify public health departments and evaluate transplant recipients from donors with signs of possible encephalitis to facilitate early diagnosis and targeted treatment. Organ procurement organizations and transplant centers should be aware of the potential for Balamuthia infection in donors with possible encephalitis and also assess donors carefully for signs of neurologic infection that may have been misdiagnosed as stroke or as noninfectious forms of encephalitis.

Giardia duodenalis is the most common intestinal parasite of humans in the USA, but the risk factors for sporadic (non-outbreak) giardiasis are not well described. The Centers for Disease Control and Prevention and the Colorado and Minnesota public health departments conducted a case-control study to assess risk factors for sporadic giardiasis in the USA. Cases (N = 199) were patients with non-outbreak-associated laboratory-confirmed Giardia infection in Colorado and Minnesota, and controls (N = 381) were matched by age and site. Identified risk factors included international travel (aOR = 13.9; 95% CI 4.9–39.8), drinking water from a river, lake, stream, or spring (aOR = 6.5; 95% CI 2.0–20.6), swimming in a natural body of water (aOR = 3.3; 95% CI 1.5–7.0), male–male sexual behaviour (aOR = 45.7; 95% CI 5.8–362.0), having contact with children in diapers (aOR = 1.6; 95% CI 1.01–2.6), taking antibiotics (aOR = 2.5; 95% CI 1.2–5.0) and having a chronic gastrointestinal condition (aOR = 1.8; 95% CI 1.1–3.0). Eating raw produce was inversely associated with infection (aOR = 0.2; 95% CI 0.1–0.7). Our results highlight the diversity of risk factors for sporadic giardiasis and the importance of non-international-travel-associated risk factors, particularly those involving person-to-person transmission. Prevention measures should focus on reducing risks associated with diaper handling, sexual contact, swimming in untreated water, and drinking untreated water.

A decade after reporting its last case of Guinea worm disease (GWD), a waterborne parasitic disease targeted for eradication, Chad reported 20 confirmed human cases from 17 villages-10 cases in 2010 and 10 cases in 2011. In 2012, the first GWD dog infections were diagnosed. We conducted a case-control study during April-May 2012 to identify human transmission risk factors and epidemiologic links. We recruited 19 cases and 45 controls matched by age, sex, time, and location of exposure based on the case patients' periods of infection 10-14 months earlier. Data were analyzed with simple conditional logistic regression models using Firth penalized likelihood methods. Unusually, GWD did not appear to be associated with household primary water sources. Instead, secondary water sources, used outside the village or other nonprimary sources used at home, were risk factors (matched odds ratio = 38.1, 95% confidence interval = 1.6-728.2). This study highlights the changing epidemiology of GWD in Chad-household primary water sources were not identified as risk factors and few epidemiologic links were identified between the handfuls of sporadic cases per year, a trend that continues. Since this investigation, annual dog infections have increased, far surpassing human cases. An aquatic paratenic host is a postulated mode of transmission for both dogs and humans, although fish could not be assessed in this case-control study due to their near-universal consumption. GWD's evolving nature in Chad underscores the continued need for interventions to prevent both waterborne and potential foodborne transmission until the true mechanism is established.

A liver, heart, iliac vessel and two kidneys were recovered from a 39-year-old man who died of traumatic head injury and were transplanted into five recipients. The liver recipient 18 days posttransplantation presented with headache, ataxia and fever, followed by rapid neurologic decline and death. Diagnosis of granulomatous amebic encephalitis was made on autopsy. Balamuthia mandrillaris infection was confirmed with immunohistochemical and polymerase chain reaction (PCR) assays. Donor and recipients' sera were tested for B. mandrillaris antibodies. Donor brain was negative for Balamuthia by immunohistochemistry and PCR; donor serum Balamuthia antibody titer was positive (1:64). Antibody titers in all recipients were positive (range, 1:64-1:512). Recipients received a four- to five-drug combination of miltefosine or pentamidine, azithromycin, albendazole, sulfadiazine and fluconazole. Nausea, vomiting, elevated liver transaminases and renal insufficiency were common. All other recipients survived and have remained asymptomatic 24 months posttransplant. This is the third donor-derived Balamuthia infection cluster described in solid organ transplant recipients in the United States. As Balamuthia serologic testing is only available through a national reference laboratory, it is not feasible for donor screening, but may be useful to determine exposure status in recipients and to help guide chemotherapy.

To describe the trend of Acanthamoeba keratitis case reports following an outbreak and the recall of a multipurpose contact lens disinfection solution. Acanthamoeba keratitis is a serious eye infection caused by the free-living amoeba Acanthamoeba that primarily affects contact lens users.A convenience sample of 13 ophthalmology centers and laboratories in the USA, provided annual numbers of Acanthamoeba keratitis cases diagnosed between 1999-2009 and monthly numbers of cases diagnosed between 2007-2009. Data on ophthalmic preparations of anti-Acanthamoeba therapies were collected from a national compounding pharmacy.Data from sentinel site ophthalmology centers and laboratories revealed that the yearly number of cases gradually increased from 22 in 1999 to 43 in 2003, with a marked increase beginning in 2004 (93 cases) that continued through 2007 (170 cases; p0.0001). The outbreak identified from these sentinel sites resulted in the recall of a contact lens disinfecting solution. There was a statistically significant (p ≤ 0.0001) decrease in monthly cases reported from 28 cases in June 2007 (following the recall) to seven cases in June 2008, followed by an increase (p = 0.0004) in reported cases thereafter; cases have remained higher than pre-outbreak levels. A similar trend was seen in prescriptions for Acanthamoeba keratitis chemotherapy. Cases were significantly more likely to be reported during summer than during other seasons.The persistently elevated number of reported cases supports the need to understand the risk factors and environmental exposures associated with Acanthamoeba keratitis. Further prevention efforts are needed to reduce the number of cases occurring among contact lens wearers.

We report a 62-year-old male who presented status post lung transplantation with subcutaneous nodules. One week later, he showed signs of altered mental status; brain imaging demonstrated mass effect in the cerebellum and meningoencephalitis. In spite of treatment with a broad range of antimicrobials, he died. A punch biopsy of the skin lesions showed a superficial and deep mixed inflammatory infiltrate admixed with large mononuclear cells. A diagnosis of cutaneous amoebiasis was made and the amoebae were identified as Acanthamoeba spp. based on immunofluorescent stains and PCR assays. Cutaneous Acanthamoebiasis is a rare infection in immunocompro- mised patients, particularly organ recipients. It is important that this entity is included in the differential diagnosis of immunocompromised patients who have cutaneous infections that are not responding to antibiotics. An early diagnosis is crucial since cutaneous Acanthamoebiasis can disseminate to the central nervous system and cause granulomatous amoebic encephalitis (GAE), which is usually fatal.

Estimates of foodborne illness can be used to direct food safety policy and interventions. We used data from active and passive surveillance and other sources to estimate that each year 31 major pathogens acquired in the United States caused 9.4 million episodes of foodborne illness (90% credible interval [CrI] 6.6–12.7 million), 55,961 hospitalizations (90% CrI 39,534–75,741), and 1,351 deaths (90% CrI 712–2,268). Most (58%) illnesses were caused by norovirus, followed by nontyphoidal Salmonella spp. (11%), Clostridium perfringens (10%), and Campylobacter spp. (9%). Leading causes of hospitalization were nontyphoidal Salmonella spp. (35%), norovirus (26%), Campylobacter spp. (15%), and Toxoplasma gondii (8%). Leading causes of death were nontyphoidal Salmonella spp. (28%), T. gondii (24%), Listeria monocytogenes (19%), and norovirus (11%). These estimates cannot be compared with prior (1999) estimates to assess trends because different methods were used. Additional data and more refined methods can improve future estimates.

Subtyping was conducted in late 2007 on 57 Cryptosporidium specimens from sporadic cases in Colorado, Idaho, New Mexico, and Iowa. One previously rare Cryptosporidium hominis subtype was indentified in 40 cases (70%) from all four states, and the Cryptosporidium horse genotype was identified in a pet shop employee with severe clinical symptoms.

Premarket standardized testing for Acanthamoeba spp. is warranted., An outbreak of Acanthamoeba keratitis, a rare, potentially blinding, corneal infection, was detected in the United States in 2007; cases had been increasing since 2004. A case–control study was conducted to investigate the outbreak. We interviewed 105 case-patients from 30 states and 184 controls matched geographically and by contact lens use. Available contact lenses, cases, solutions, and corneal specimens from case-patients were cultured and tested by molecular methods. In multivariate analyses, case-patients had significantly greater odds of having used Advanced Medical Optics Complete Moisture Plus (AMOCMP) solution (odds ratio 16.9, 95% confidence interval 4.8–59.5). AMOCMP manufacturing lot information was available for 22 case-patients, but none of the lots were identical. Three unopened bottles of AMOCMP tested negative for Acanthamoeba spp. Our findings suggest that the solution was not intrinsically contaminated and that its anti-Acanthamoeba efficacy was insufficient. Premarket standardized testing of contact lens solutions for activity against Acanthamoeba spp. is warranted.

In 2006, Ghana ranked second in Guinea worm disease (GWD) incidence and reported a previously undocumented 20% prevalence of worm breakage. A prospective study was conducted in 2007 to validate and describe worm breakage and determinants. Among 221 patients with known outcomes, the worm breakage rate observed was 46%. After controlling for demographics, worm and wound presentation, and treatment course and provision, worm breakage was associated with narrow-diameter worms (< 2 mm) (adjusted odds ratio [AOR] 2.79; 95% confidence interval [CI] = 1.03-7.53). Protective factors against worm breakage included antibiotic ointment use (AOR 0.31; 95% CI = 0.14-0.70), bandage protocol compliance (AOR: 0.38; 95% CI = 0.16-0.89), intact bandages (AOR 0.27; 95% CI = 0.09-0.82), and bloody compared with dry wounds (AOR 0.09; 95% CI = 0.01-0.7). The high worm breakage rate observed warrants improvement in case management and patient care. Adherence to established treatment protocols should be facilitated through improved provider training and supervision to reduce the disabling consequences of broken worms.

Acanthamoebae are free-living amoebae found in the environment, including soil, freshwater, brackish water, seawater, hot tubs, and Jacuzzis. Acanthamoeba species can cause keratitis, a painful vision-threatening infection of the cornea, and fatal granulomatous encephalitis in humans. More than 20 species of Acanthamoeba belonging to morphological groups I, II, and III distributed in 15 genotypes have been described. Among these, Acanthamoeba castellanii , A . polyphaga , and A. hatchetti are frequently identified as causing Acanthamoeba keratitis (AK). Improper contact lens care and contact with nonsterile water while wearing contact lenses are known risk factors for AK. During a recent multistate outbreak, AK was found to be associated with the use of Advanced Medical Optics Complete MoisturePlus multipurpose contact lens solution, which was hypothesized to have had insufficient anti- Acanthamoeba activity. As part of the investigation of that outbreak, we compared the efficacies of 11 different contact lens solutions against cysts of A. castellanii , A. polyphaga , and A. hatchetti (the isolates of all species were genotype T4), which were isolated in 2007 from specimens obtained during the outbreak investigation. The data, generated with A. castellanii , A. polyphaga , and A. hatchetti cysts, suggest that the two contact lens solutions containing hydrogen peroxide were the only solutions that showed any disinfection ability, with 0% and 66% growth, respectively, being detected with A. castellanii and 0% and 33% growth, respectively, being detected with A. polyphaga . There was no statistically significant difference in disinfection efficacy between the 11 solutions for A. hatchetti .

Balamuthia mandrillaris is a rare cause of human infection, but when infections do occur, they result in high rates of morbidity and mortality. A case of disseminated Balamuthia infection is presented. Early diagnosis and initiation of recommended therapy are essential for increased chances of successful outcomes.

Many studies have evaluated the role of Cryptosporidium spp. in outbreaks of enteric illness, but few studies have evaluated sporadic cryptosporidiosis in the United States. To assess the risk factors for sporadic cryptosporidiosis among immunocompetent persons, a matched case-control study was conducted in seven sites of the Foodborne Diseases Active Surveillance Network (FoodNet) involving 282 persons with laboratory-identified cryptosporidiosis and 490 age-matched and geographically matched controls. Risk factors included international travel (odds ratio [OR] = 7.7; 95% confidence interval [95% CI] = 2.7 to 22.0), contact with cattle (OR = 3.5; 95% CI = 1.8 to 6.8), contact with persons >2 to 11 years of age with diarrhea (OR = 3.0; 95% CI = 1.5 to 6.2), and freshwater swimming (OR = 1.9; 95% CI = 1.049 to 3.5). Eating raw vegetables was protective (OR = 0.5; 95% CI = 0.3 to 0.7). This study underscores the need for ongoing public health education to prevent cryptosporidiosis, particularly among travelers, animal handlers, child caregivers, and swimmers, and the need for further assessment of the role of raw vegetables in cryptosporidiosis.

In October 2001, two envelopes containing Bacillus anthracis spores were processed at the Washington, D.C., Processing and Distribution Center of the U.S. Postal Service; inhalational anthrax developed in four workers at this facility. More than 2,000 workers were advised to complete 60 days of postexposure prophylaxis to prevent inhalational anthrax. Interventions to promote adherence were carried out to support workers, and qualitative information was collected to evaluate our interventions. A quantitative survey was administered to a convenience sample of workers to assess factors influencing adherence. No anthrax infections developed in any workers involved in the interventions or interviews. Of 245 workers, 98 (40%) reported full adherence to prophylaxis, and 45 (18%) had completely discontinued it. Anxiety and experiencing adverse effects to prophylaxis, as well as being

Background. Primary amoebic meningoencephalitis (PAM) is a rapidly progressing waterborne illness that predominately affects children and is nearly always fatal. PAM is caused by Naegleria fowleri, a free-living amoeba found in bodies of warm freshwater worldwide. Methods. We reviewed exposure location, clinical signs and symptoms, diagnostic modalities, and treatment from confirmed cases of PAM diagnosed in the United States during 1937–2013. Patients were categorized into the early (ie, flu-like symptoms) or late (ie, central nervous system signs) group on the basis of presenting clinical characteristics. Here, we describe characteristics of the survivors and decedents. Result. The median age of the patients was 12 years (83% aged 18 years); males (76%) were predominately affected (N = 142). Most infections occurred in southern-tier states; however, 4 recent infections were acquired in northern states: Minnesota (2), Kansas (1), and Indiana (1). Most (72%) of the patients presented with central nervous system involvement. Cerebrospinal fluid analysis resembled bacterial meningitis with high opening pressures, elevated white blood cell counts with predominantly neutrophils (median, 2400 cells/μL [range, 5–26 000 cells/μL]), low glucose levels (median, 23 mg/dL [range, 1–92 mg/dL]), and elevated protein levels (median, 365 mg/dL [range, 24–1210 mg/dL]). Amoebas found in the cerebrospinal fluid were diagnostic, but PAM was diagnosed foronly 27% of the patients before death. Imaging results were abnormal in approximately three-fourths of the patients but were not diagnostic for amoebic infection. Three patients in the United States survived. Conclusions. To our knowledge, this is the first comprehensive clinical case series of PAM presented in the United States. PAM is a fatal illness with limited treatment success and is expanding into more northern regions. Clinicians who suspect that they have a patient with PAM should contact the US Centers for Disease Control and Prevention at 770–488–7100 (available 24 hours/day, 7 days/week) to discuss diagnostic testing and treatment options (see cdc.gov/naegleria).

Granulomatous amebic encephalitis (GAE) from Balamuthia mandrillaris, a free-living ameba, has a case fatality rate exceeding 90% among recognized cases in the United States. In August 2010, a GAE cluster occurred following transplantation of infected organs from a previously healthy landscaper in Tucson, Arizona, USA, who died from a suspected stroke. As B. mandrillaris is thought to be transmitted through soil, a serologic survey of landscapers and a comparison group of blood donors in southern Arizona was performed. Three (3.6%) of 83 serum samples from landscapers and 11 (2.5%) of 441 serum samples from blood donors were seropositive (p = 0.47). On multivariable analysis, county of residence was associated with seropositivity, whereas age, sex, and ethnicity were not. Exposure to B. mandrillaris, previously unexamined in North America, appears to be far more common than GAE in Southern Arizona. Risk factors for disease progression and the ameba's geographic range should be examined.

Primary amebic meningoencephalitis (PAM) caused by the free-living ameba Naegleria fowleri is a rare but rapidly fatal disease of the central nervous system (CNS) affecting predominantly young, previously healthy persons. No effective chemotherapeutic prophylaxis or treatment has been identified. Recently, three transplant-associated clusters of encephalitis caused by another free-living ameba, Balamuthia mandrillaris, have occurred, prompting questions regarding the suitability of extra-CNS solid organ transplantation from donors with PAM. During 1995–2012, 21 transplant recipients of solid organs donated by five patients with fatal cases of PAM were reported in the United States. None of the recipients developed PAM and several recipients tested negative for N. fowleri by serology. However, historical PAM case reports and animal experiments with N. fowleri, combined with new post-mortem findings from four PAM patients, suggest that extra-CNS dissemination of N. fowleri can occur and might pose a risk for disease transmission via transplantation. The risks of transplantation with an organ possibly harboring N. fowleri should be carefully weighed for each individual recipient against the potentially greater risk of delaying transplantation while waiting for another suitable organ. In this article we present a case series and review existing data to inform such risk assessments.

We describe 11 cases of suspected Dracunculus medinensis infection in which the worm recovered was identified as Onchocerca volvulus. Identification was based on morphology of the examined specimen.

Background The burden of nonoutbreak-related Giardia infections in the US is poorly understood, with little information on its impact on people's lives and on unusual manifestations of infection. This study was designed with the objectives of better defining the impact of infection, examining the occurrence of extraintestinal manifestations, and determining risk factors for delayed treatment of infection. Methods Foodborne Diseases Active Surveillance Network surveillance was used to identify persons with nonoutbreak-related, laboratory-confirmed Giardia infection. People were enrolled into the Risk Factor arm and the Delayed Enrollment arm. Detailed questionnaires collected information on clinical manifestations, impact on activities of daily living, health care utilization, and treatment. Results The study enrolled 290 people. Multivariate predictors of delayed study enrollment, a surrogate for delayed diagnosis of Giardia , included intermittent diarrheal symptoms, delayed time to first health care visit, and income. Decreased ability to participate in one's activities of daily living was reported by 210 (72.4%) participants. Appropriate therapeutic agent for Giardia was received by 237 (81.7%) by the time of study enrollment. Extraintestinal manifestations of Giardia were reported by 72 (33.8%) persons who enrolled in the Risk Factor arm. Conclusions The presence of intermittent diarrhea contributes to delayed health-seeking behavior and to delayed diagnosis of Giardia . More study is needed to determine if this symptom can help distinguish Giardia from other causes of infectious diarrhea. The occurrence of extraintestinal manifestations of Giardia infection does not appear to be rare, and merits further study.