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We tested for Rift Valley fever virus (RVFV) from at least 15 species of non-human primates. RVFV IgG/IgM antibodies were detected in 3.7% (2 out of 53) of chimpanzees (Pan troglodytes) and in 1.4% (1 out of 72) of unidentified non-human primate species. This study was the first investigation of RVFV in monkeys in Cameroon. [ABSTRACT FROM AUTHOR]

Key Clinical Message: We report a case of febrile illness that was presented with mild symptoms. However, laboratory investigation confirmed a malaria and Rift Valley fever co‐infection. Healthcare providers in settings endemic with several infectious diseases should seek rolling out possibilities of other infections prior to starting treatment for achieving effective case management with less resources and better safety of patients. Here we report a case of febrile illness that confirmed to be a co‐infection of malaria and Rift Valley fever. The patient was initially diagnosed with malaria and started on treatment immediately. However, due to the lack of response to the treatment further laboratory investigations were pursued. [ABSTRACT FROM AUTHOR]

Rift Valley fever (RVF) is a severe zoonotic mosquito‐borne disease that represents an important threat to human and animal health, with major public health and socioeconomic impacts. This disease is endemic throughout many African countries and the Arabian Peninsula. This systematic review with meta‐analysis was conducted to determine the RVF prevalence in humans, mosquitoes and other animal species in Africa. The review also provides contemporary data on RVF case fatality rate (CFR) in humans. In this systematic review with meta‐analysis, a comprehensive literature search was conducted on the PubMed, Embase, Web of Science and Global Index Medicus databases from January 2000 to June 2022 to identify relevant studies. Pooled CFR and prevalence estimates were calculated using the random‐effects model. Subgroup analysis and sensitivity analysis were performed, and the I2‐statistic was used to investigate a potential source of heterogeneity. A total of 205 articles were included in the final analysis. The overall RVF CFR in humans was found to be 27.5% [95% CI = 8.0–52.5]. The overall pooled prevalence was 7.8% [95% CI = 6.2–9.6] in humans and 9.3% [95% CI = 8.1–10.6] in animals, respectively. The RVF prevalence in individual mosquitoes ranged from 0.0% to 25%. Subgroup analysis showed substantial heterogeneity with respect to geographical regions and human categories. The study shows that there is a correspondingly similar prevalence of RVF in human and animals; however, human CFR is much higher than the observed prevalence. The lack of a surveillance programme and the fact that this virus has subclinical circulation in animals and humans could explain these observations. The implementation of a One Health approach for RVF surveillance and control would be of great interest for human and animal health. [ABSTRACT FROM AUTHOR]

Dragonfly/damselfly naiads have the potential to control mosquitoes, and indirectly the diseases they carry, due to their extensive predation on mosquito larvae. Experimental studies have measured the effectiveness of individual dragonfly/damselfly naiads in controlling mosquitoes by introducing them to mosquito larvae and counting the number of larvae eaten in a given time period (i.e. predation success).Without a quantitative synthesis, however, such individual measures are unable to provide a generalized estimation about the effectiveness of dragonflies/damselflies as biological mosquito control agents. To achieve this, we assembled a database containing 485 effect sizes across 31 studies on predation successes of 47 species of commonly found dragonfly/damselfly naiads on nine species of mosquito larvae belonging to Aedes, Anopheles and Culex. These studies covered 14 countries across Asia, Africa and South and North America, where mosquitoes are the vectors of Chikungunya, Dengue, Japanese encephalitis, Lymphatic filariasis, Malaria, Rift Valley fever, West Nile fever, Yellow fever and Zika.Using this database, we conducted a meta‐analysis to estimate the average predation success per day by a single individual dragonfly/damselfly naiad on these mosquito larvae as a generalized measure of the effectiveness of dragonflies/damselflies for mosquito control. We also built an interaction network for predator‐dragonflies/damselflies and prey‐mosquitoes and the diseases they vector to understand the functioning of this important predator‐prey network.Our results showed that mosquito larvae were significantly reduced through predation by dragonfly/damselfly naiads. Within experimental containers, a single individual dragonfly/damselfly naiad can eat on average 40 (95% confidence intervals [CIs] = 20, 60) mosquito larvae per day, equivalent to a reduction of the mosquito larval population by 45% (95% CIs = 30%, 59%) per day. The average predation success did not significantly vary among Aedes, Anopheles and Culex mosquitoes or among the four (I–IV) mosquito larval stages.These results provide strong evidence that dragonflies/damselflies can be effective biological control agents of mosquitoes, and environmental planning to promote them could lower the risk of spreading mosquito‐borne diseases in an environmentally friendly and cost‐effective manner. [ABSTRACT FROM AUTHOR]

Climate change is having a significant impact on viral transmission, leading to increased viral persistence and reactivation. Rising temperatures and changing environmental conditions are altering the behavior of disease vectors like mosquitoes, allowing them to colonize new areas and spread diseases to previously unaffected populations. Climbing temperatures also shorten viral replication times and incubation periods, increasing transmission rates. Changing precipitation levels and humidity create new breeding sites for mosquitoes and allow viruses to persist longer. Climate change also increases the risk of viral spillover events between wildlife species and may worsen viral respiratory diseases. It is crucial for the medical and scientific community to deepen their understanding of these climate-virus connections to enhance prevention and response capabilities. [Extracted from the article]

Rift Valley fever is an important yet ignored viral hemorrhagic fever claiming many lives of African and Arabian countries over the past decade. Unfortunately, a recent outbreak of Rift Valley fever is currently ravaging in Mauritania. Death toll is rising continuously with 23 deaths reported in the month of October, 2022. Our article aims to shed light on the ongoing Rift Valley fever outbreak and recommendations to eradicate this potential threat to public health. Online databases including PubMed, the Lancet, and Science Direct as well as conferences, news, and press releases were used to for data collection. All the available medical literature related to Rift Valley fever in Mauritania were taken into consideration while writing the manuscript. As of October 17, 2022, 47 cases have been documented out of which 23 are dead. Case fatality rate has been reached to 49% which has given a wakeup call to the authorities. Efforts are being made by the concerned authorities and World Health Organization to halt the progression of this outbreak. Further investigations are required to completely eradicate the recurrent outbreaks in Mauritania especially in the area of vaccine development. Active involvement of public with the government authorities is of extreme significance in combating this disease. [ABSTRACT FROM AUTHOR]

Background: Rift Valley fever virus (RVFV) is the cause of one of the most important mosquito‐borne emerging diseases negatively affecting the health of humans and animals, particularly in Africa. In Ethiopia, the status of RVFV and the existence of potential vectors are unknown. Objectives: This study aimed to survey the mosquito vectors of RVFV and the detection of the virus in selected sites (Batu, Hawassa, Arba Minch and Borana) in Ethiopia. Methods: CDC light traps baited with the sugar‐yeast solution were set up at various locations for a total of 29 trap nights. Mosquitoes identification were made morphologically using a stereomicroscope and for RVFV detection by reverse transcriptase‐polymerase chain reaction (RT‐PCR). Results: Among a total of 132 trap efforts conducted, 60 (45%) captured the mosquitoes. A total of 1576 adult mosquitoes were collected and identified. Including Aedes (n = 407; 25.8%), Anopheles (n = 493; 32.3%), Culex (n = 466; 29.6%) and Mansonia (n = 210; 13.32%). The genome material of RVFV was not detected by RT‐PCR. Conclusions: The existence of a potential Aedes species may pose a risk for the occurrence of the RVF outbreak in Ethiopia. Based on the current study, we recommend further monitoring for potential mosquito vectors of RVFV, particularly with a view to targeting the seasons during which the mosquitoes can be abundant along with a serological survey of susceptible hosts. [ABSTRACT FROM AUTHOR]

The June‐October 2020 growing season was characterized by sustained and extreme flooding across the African Sahel. One consequence of flooding events such as this is outbreaks of vector borne diseases (VBDs) which are often associated with climate anomalies. In this study, data from the soil moisture active passive (SMAP) mission is used with other soil moisture and precipitation data to show that the 2020 Sahelian growing season was the most extreme over the past four decades, ranking first in seasonally accumulated precipitation, which on average exceeded the climatology by around 300 mm. VBD outbreaks of Rift Valley fever and Chikungunya followed in Mauritania/Senegal and Chad, respectively. In some cases, soil moisture is a better indicator of VBD outbreak risk than precipitation, which has so far been more commonly used in studies of VBD outbreaks. It is expected that this finding will inform future monitoring and prediction efforts for VBD risk. Plain Language Summary: Extreme rainfall and flooding can be harmful to society in many ways; this study examines the case study of flooding that affected the African Sahel during the summer of 2020. One consequence of flooding events is the increased risk of vector‐borne diseases outbreaks. These outbreaks are often linked with anomalies in climate variables such as precipitation, temperature, and vegetation conditions which prime disease vector habitats. This study uses satellite‐measured soil moisture information to assess the 2020 Sahel flooding and its relation to outbreaks of Rift Valley fever and Chikungunya vector‐borne disease outbreaks. It is shown that this event was very extreme in the context of the historical data record, and soil moisture is shown to be a valuable information source for indicating the potential risk areas of disease outbreaks. Key Points: Above‐normal precipitation of up to 600 mm locally led to flooding in the African Sahel during the 2020 growing season (June‐October)Precipitation and surface soil moisture data indicate that this event was among the most extreme in the region in recent decadesThis event is linked with disease outbreaks, and soil moisture is potentially a better indicator of outbreak risk than precipitation alone [ABSTRACT FROM AUTHOR]

Bats are the natural reservoir host for many pathogenic and non‐pathogenic viruses, potentially spilling over to humans and domestic animals directly or via an intermediate host. The ongoing COVID‐19 pandemic is the continuation of virus spillover events that have taken place over the last few decades, particularly in Asia and Africa. Therefore, these bat‐associated epidemics provide a significant number of hints, including respiratory cellular tropism, more intense susceptibility to these cell types, and overall likely to become a pandemic for the next spillover. In this systematic review, we analysed data to insight, through bat‐originated spillover in Asia and Africa. We used STATA/IC‐13 software for descriptive statistics and meta‐analysis. The random effect of meta‐analysis showed that the pooled estimates of case fatality rates of bat‐originated viral zoonotic diseases were higher in Africa (61.06%, 95%CI: 50.26 to 71.85, l2% = 97.3, p < 0.001). Moreover, estimates of case fatality rates were higher in Ebola (61.06%; 95%CI: 50.26 to 71.85, l2% = 97.3, p < 0.001) followed by Nipah (55.19%; 95%CI: 39.29 to 71.09, l2% = 94.2, p < 0.001), MERS (18.49%; 95%CI: 8.19 to 28.76, l2% = 95.4, p < 0.001) and SARS (10.86%; 95%CI: 6.02 to 15.71, l2% = 85.7, p < 0.001) with the overall case fatality rates of 29.86 (95%CI: 29.97 to 48.58, l2% = 99.0, p < 0.001). Bat‐originated viruses have caused several outbreaks of deadly diseases, including Nipah, Ebola, SARS and MERS in Asia and Africa in a sequential fashion. Nipah virus emerged first in Malaysia, but later, periodic outbreaks were noticed in Bangladesh and India. Similarly, the Ebola virus was detected in the African continent with neurological disorders in humans, like Nipah, seen in the Asian region. Two important coronaviruses, MERS and SARS, were introduced, both with the potential to infect respiratory passages. This paper explores the dimension of spillover events within and/or between bat–human and the epidemiological risk factors, which may lead to another pandemic occurring. Further, these processes enhance the bat‐originated virus, which utilises an intermediate host to jump into human species. [ABSTRACT FROM AUTHOR]

The newly established virus family Phenuiviridae in Bunyavirales harbors viruses infecting three kingdoms of host organisms (animals, plants, and fungi), which is rare in known virus families. Many phenuiviruses are arboviruses and replicate in two distinct hosts (e.g., insects and humans or rice). Multiple phenuivirid species, such as Dabie bandavirus, Rift Valley fever phlebovirus, and Rice stripe tenuivirus, are highly pathogenic to humans, animals, or plants. They impose heavy global burdens on human health, livestock industry, and agriculture and are research hotspots. In recent years the taxonomy of Phenuiviridae has been expanded greatly, and research on phenuiviruses has made significant progress. With these advances, this review drew a novel panorama regarding the biomedical significance, distribution, morphology, genomics, taxonomy, evolution, replication, transmission, pathogenesis, and control of phenuiviruses, to aid researchers in various fields to recognize this highly adaptive and important virus family and conduct relevant risk analysis. Key Points/Highlights: 1.This review draws a novel panorama for the virus family Phenuiviridae.2.Phenuiviridae has importance in the health of humans, animals, and plants.3.Structures, functions, and evolution of phenuivirid genes were reviewed.4.Pathogenesis, epidemiology, and control of phenuiviruses were reviewed. [ABSTRACT FROM AUTHOR]

Summary: Zoonotic diseases, such as brucellosis, Q fever and Rift Valley fever (RVF) caused by Brucella spp., Coxiella burnetii and RVF virus, respectively, can have devastating effects on human, livestock, and wildlife health and cause economic hardship due to morbidity and mortality in livestock. Coinfection with multiple pathogens can lead to more severe disease outcomes and altered transmission dynamics. These three pathogens can alter host immune responses likely leading to increased morbidity, mortality and pathogen transmission during coinfection. Developing countries, such as those commonly afflicted by outbreaks of brucellosis, Q fever and RVF, have high disease burden and thus common coinfections. A literature survey provided information on case reports and studies investigating coinfections involving the three focal diseases. Fifty five studies were collected demonstrating coinfections of Brucella spp., C. burnetii or RVFV with 50 different pathogens, of which 64% were zoonotic. While the literature search criteria involved 'coinfection', only 24/55 studies showed coinfections with direct pathogen detection methods (microbiology, PCR and antigen test), while the rest only reported detection of antibodies against multiple pathogens, which only indicate a history of co‐exposure, not concurrent infection. These studies lack the ability to test whether coinfection leads to changes in morbidity, mortality or transmission dynamics. We describe considerations and methods for identifying ongoing coinfections to address this critical blind spot in disease risk management. [ABSTRACT FROM AUTHOR]

Galidesivir (BCX4430) is an adenosine nucleoside analog broadly active in cell culture against multiple RNA virus families, and active in animal models of viral diseases associated with Ebola, Marburg, yellow fever, Zika, and Rift Valley fever. Current studies demonstrated the pharmacokinetics and safety of the first‐in‐human evaluations of galidesivir as intramuscular (IM) and intravenous (IV) formulations. Two double‐blind, placebo‐controlled, dose‐ranging studies were conducted enrolling 126 healthy subjects. Study 1 evaluated the safety and tolerability of IM galidesivir over single day dosing, single day dosing ± lidocaine, and 7‐day dosing with lidocaine. Study 2 evaluated the safety and tolerability of single ascending doses of IV galidesivir. Safety and tolerability were evaluated via clinical and laboratory monitoring. The plasma concentration–time profile of galidesivir at doses 0.3 to 10 mg/kg IM was characterized by rapid absorption, an initial rapid distribution and clearance phase, and an extended terminal elimination phase. The initial rapid distribution and extended terminal elimination were mimicked in the profile of galidesivir at doses 5 to 20 mg/kg IV. No fatal events or related serious adverse events were reported. No clinically significant dose‐related trends in laboratory values, vital signs, electrocardiograms, or echocardiograms were noted. Galidesivir was safe and generally well tolerated. [ABSTRACT FROM AUTHOR]

Africa is united with other frontline regions in urging wealthy nations to finally step up, if for no other reason than that the crises in Africa will sooner rather than later spread and engulf all corners of the globe, by which time it may be too late to effectively respond. I Wealthy nations must step up support for Africa and vulnerable countries in addressing past, present and future impacts of climate change i . [Extracted from the article]

A new rising incidence of Rift Valley fever (RVF) among livestock and humans in the African continent during the COVID‐19 pandemic has become of increasing concern. We analyzed the different ways COVID‐19 has contributed to the increase in RVF cases and how it has impacted the interventions allocated to the disease by comparing it with the status of the disease before the pandemic. There is enough evidence to conclude that the COVID‐19 pandemic has impacted the efforts being taken to prevent outbreaks of RVF. Therefore, with no definitive treatment in place and inadequate preventive measures and disease control, RVF may potentially lead to a future epidemic unless addressed urgently. [ABSTRACT FROM AUTHOR]

I Wealthy nations must step up support for Africa and vulnerable countries in addressing past, present and future impacts of climate change i The 2022 report of the Intergovernmental Panel on Climate Change (IPCC) paints a dark picture of the future of life on earth, characterised by ecosystem collapse, species extinction, and climate hazards such as heatwaves and floods.1 These are all linked to physical and mental health problems, with direct and indirect consequences of increased morbidity and mortality. Ahead of this meeting, we - as health journal editors from across the continent - call for urgent action to ensure it is the COP that finally delivers climate justice for Africa and vulnerable countries. [Extracted from the article]

Ahead of this meeting, we - as health journal editors from across the continent - call for urgent action to ensure it is the COP that finally delivers climate justice for Africa and vulnerable countries. I Wealthy nations must step up support for Africa and vulnerable countries in addressing past, present and future impacts of climate change. i The 2022 report of the Intergovernmental Panel on Climate Change (IPCC) paints a dark picture of the future of life on earth, characterised by ecosystem collapse, species extinction, and climate hazards such as heatwaves and floods.1 These are all linked to physical and mental health problems, with direct and indirect consequences of increased morbidity and mortality. [Extracted from the article]

In social species, the transmission and maintenance of infectious diseases depends on the contact patterns between individuals within groups and on the interactions between groups. In southern Africa, the Cape buffalo (Syncerus caffer caffer) is a vector for many pathogens that can infect sympatric livestock. Although intra‐group contact patterns of Cape buffalo have been relatively well described, how groups interact with each other and risks for pathogen transmission remain poorly understood. We identified and compared spatial behavior and contact patterns between neighboring groups of Cape buffalo under contrasting environments: within the seasonally flooded environment of the Okavango Delta in Botswana and the semi‐arid environment of northern Kruger National Park in South Africa. We used telemetry data collected between 2007 and 2015 from 10 distinct groups. We estimated seasonal overlap and proximity between home ranges of pairwise neighboring groups, and we quantified seasonal contact patterns between these groups. We defined contact patterns within variable spatiotemporal windows compatible with the transmission of diseases carried by the Cape buffalo: bovine tuberculosis, brucellosis, and Rift Valley fever (mosquito‐borne transmission). We examined the effects of habitat and distance to water on contact location. In both study populations, neighboring buffalo groups were highly spatially segregated in the dry and rainy seasons. Inter‐group contact patterns were characterized by very few direct and short‐term indirect (within 0–2 days) contacts, lasting on average 1 hour and 2 hours, respectively. Contact patterns were generally consistent across populations and seasons, suggesting species‐specific behavior. In the drier study site, the probability of indirect and vector‐borne contacts generally decreased during the dry season with increasing distance to water. In the seasonally flooded area, only the probability of vector‐borne contact decreased with increasing distance to water. Our results highlight the importance of dry season water availability in influencing the dynamics of indirectly transmitted Cape buffalo pathogens but only in areas with low water availability. The results from this study have important implications for future modeling of pathogen dynamics in a single host, and the ecology and management of Cape buffalo at the landscape level. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society. We found that in 2 distinct populations, home ranges of Cape buffalos from neighboring groups were spatially segregated with minimal overlap and very little direct contacts. In drier areas, scarce water sources might be places where indirect contact is more likely to occur, and management measures should focus on manipulating water distribution so that Cape buffalo groups establish and use exclusive home ranges to reduce potential for disease spread. [ABSTRACT FROM AUTHOR]

Background: West Nile Disease (WND) is a zoonotic mosquito‐borne infection involving viral pathogens, human and animal hosts, vectors and environment. Cooperation among medical, veterinary and entomological fields has been promoted by the Italian Public Health Authorities, and an integrated West Nile Virus (WNV) Surveillance Plan has been in force in Italy since 2016 to prevent the transmission risk of WND to humans through an early detection of viral circulation by animal and entomological surveillance. This managing model is unique in Europe. Objectives: This survey aimed at presenting the 'One Health' approach applied in 2016 to the first autochthonous human case of West Nile Neuroinvasive Disease (WNND) in Sicily (Southern Italy). Methods: Serological (anti‐WNV IgM and IgG ELISA, anti‐WNV neutralizing antibodies) and molecular tests were conducted on blood, liquor and urine of a 38‐year‐old man with encephalitis and meningitis. Overall, 2704 adult culicides from 160 mosquito catches were morphologically identified. Female mosquitoes were analysed in pools for WNV RNA detection. Serological (anti‐WNV IgM and IgG ELISA) and molecular analyses for WNV were carried out in 11 horses, 271 chickens and two dogs sampled in farms around the man's residence. Results and conclusions: WNND was confirmed by serological analysis on patient's liquor and serum. Collected mosquito species included Culex pipiens (93.56%, CI95% 92.64%–94.49%), Aedes albopictus (5.25%, CI95% 4.41%–6.09%), Culex hortensis (0.59%, CI95% 0.30%–0.88%), Culiseta longiareolata (0.55%, CI95% 0.27%–0.83%) and Anopheles maculipennis s.l. (0.04%, CI95% –0.04% to 0.11%). Mosquito pools were negative for WNV RNA. Two dogs (100%) and two horses (18.18%, CI95% –4.61 to 40.97%) resulted positive for anti‐WNV specific antibodies. The 'One Health' approach allowed to report the first human neuroinvasive WND in Sicily and to confirm the local circulation of WNV in animals of the same area where the clinical case occurred, defining the autochthonous origin of the infection. [ABSTRACT FROM AUTHOR]

Background: Heat stress in tropics is generally associated with significant economic losses resulting from reduced performance, morbidity, and mortality of livestock. To avoid serious consequences of heat stress, it is imperative to better understand the physiological responses and biochemical changes under the state of altered body homeostasis during different seasons of the year. Objectives: This study aimed to evaluate the seasonal dynamics of physiological, oxidative and metabolic responses of lactating Nili‐Ravi buffaloes to the tropical climate of South China. Methods: Physiological responses including rectal temperature (RT), body surface temperature (BST) and respiratory rate (RR) along with serum biochemical and antioxidant parameters of 20 lactating Nili‐Ravi buffaloes were evaluated during different seasons of the year. Results: Higher temperature‐humidity Index (THI) during the summer season (>80) resulted in a significant increases in RR and BST as compared to the winter season. Higher oxidative stress was observed in the summer season as revealed by significantly higher MDA while lower serum antioxidant enzyme (TAC, GSH‐Px, SOD and CAT) contents. Moreover, serum cortisol was also significantly higher in summer and autumn. The levels of growth hormone and ACTH were also significantly (P < 0.05) lower in summer and autumn as compared to other seasons. The negative association of THI with physiological and antioxidant parameters was observed while it was positively associated with serum MDA and cortisol levels. Conclusions: Our study revealed moderate heat stress in lactating buffaloes in the summer season which calls for attention to avoid economic losses and animal welfare issues. [ABSTRACT FROM AUTHOR]

Summary: Plant molecular farming (PMF) is rapidly gaining traction as a viable alternative to the currently accepted paradigm of producing biologics. While the platform is potentially cheaper and more scalable than conventional manufacturing systems, expression yields and appropriate post‐translational modifications along the plant secretory pathway remain a challenge for certain proteins. Viral fusion glycoproteins in particular are often expressed at low yields in plants and, in some cases, may not be appropriately processed. Recently, however, transiently or stably engineering the host plant has shown promise as a strategy for producing heterologous proteins with more complex maturation requirements. In this study we investigated the co‐expression of a suite of human chaperones to improve the production of a human immunodeficiency virus (HIV) type 1 soluble gp140 vaccine candidate in Nicotiana benthamiana plants. The co‐expression of calreticulin (CRT) resulted in a dramatic increase in Env expression and ameliorated the endoplasmic reticulum (ER) stress response ‐ as evidenced by lower transcript abundance of representative stress‐responsive genes. The co‐expression of CRT similarly improved accumulation of glycoproteins from Epstein‐Barr virus (EBV), Rift Valley fever virus (RVFV) and chikungunya virus (CHIKV), suggesting that the endogenous chaperone machinery may impose a bottleneck for their production. We subsequently successfully combined the co‐expression of human CRT with the transient expression of human furin, to enable the production of an appropriately cleaved HIV gp140 antigen. These transient plant host engineering strategies are a promising approach for the production of high yields of appropriately processed and cleaved viral glycoproteins. [ABSTRACT FROM AUTHOR]

Modelling of emerging vector borne diseases serves as an important complement to clinical studies of modern zoonoses. This article presents an archaeo‐historic epidemiological modelling study of Rift Valley fever (RVF), using data‐driven neural network technology. RVF affects both human and animal populations, can rapidly decimate herds causing catastrophic economic hardship, and is identified as a Category A biodefense pathogen by the US Center for Disease Control. Despite recent origins circa the early 1900s, little is known about the circumstances of its inception nor the relationships between factors that affect transmission. This evidence could be vital as the disease continues to expand from its epicentre in Kenya to other parts of Africa and the Arabian Peninsula. RVF is a relevant case for archaeological/palaeopathological investigations of disease as it intersects between numerous human, animal, spatial, temporal, and sociopolitical dimensions. By integrating landscape archaeology, historical evidence, and climatic data, with evidence of human behaviour gathered through ethnoarchaeological study, this article presents an applied framework for human–animal palaeopathology. This framework aligns with the One Health approach that observes disease to be intrinsically tied to ecological and societal factors. We provide a useable alternative way of thinking about disease modelling in the present and the past, ultimately seeking to support efforts to accurately predict future impacts. Tapping into longitudinal evidence from the last 50–300 years offers a powerful way to respond to the threat zoonoses will pose to human populations around the world as the climate warms. [ABSTRACT FROM AUTHOR]

EFSA has requested the Vextornet consortium to undertake a series of spatial distribution models for seven potential mosquito vectors of Rift Valley fever virus, namely Aedes albopictus, Aedes caspius, Aedes detritus, Aedes japonicus, Aedes vexans, Culex pipiens and Culex theileri. The modelling used the distribution data held within the VectorNet archive (as at September 2018), updated by literature searches to acquire new records available since 2016. The modelling has been implemented in three phases: (i) data collection, collation and standardisation; (ii) spatial modelling for presence and absence, and the calculation of presence metrics at the country level to be compatible with the MintRisk utilities; and (iii) the spatial modelling of vector abundance, dependent on the data available. This document briefly summaries the results of the data collection, and presence and absence modelling due for delivery in December 2020. Sufficient data were amassed to produce statistically reliable spatial models of the probability of presence of all species except Ae. detritus. The models were implemented at 1 km resolution covering the whole of continental Europe, using standard modelling techniques (Boosted Regression Trees and Random Forest) implemented through the VECMAP software suite. The distribution data for the period 2016 onward will be added to the VectorNet archive when its migration to a new data warehouse within ECDC has been completed. All spatial data in the form of an ARCMAP 'package' containing summaries of the vector distribution data collected, and all model outputs have been made available online to Vectornet partners, EFSA and ECDC. This interim report will be followed by a more complete document which also includes the results of the abundance modelling, due in March 2020. [ABSTRACT FROM AUTHOR]

The overall aim of this scientific report is the assessment of the probability of entry of Rift Valley fever virus (RVFV) into the European Union (EU) through active or passive movement of vectors. Two different import pathways were considered in this report, i.e. import through flights and import via cargo on ships. The import through road transport, eggs or immature stages, and wind was not considered in this report as thought to be zero or negligible. In total 39 potential RVFV vectors were identified based on our review. Of the 39 identified potential vectors of RVFV, the five highest ranked based on their distribution in the African at‐risk countries, their potential role as vector, and their behavioural and ecological traits influencing the risk of transportation were: Anopheles pharoensis, Aedes aegypti, Mansonia uniformis, Aedes mcintoshi, and Culex quinquefasciatus. Four of these species were also detected in airports or airplanes in the EU. The estimated probability of entry of RVFV infected mosquito vectors into the EU through the passive movement of mosquito vectors by flights is medium for the Netherlands, France, Germany and Italy. These countries are heavily connected through direct flights from the 14 at‐risk countries in Africa. A low risk of RVFV import was estimated for Spain, Poland, Belgium and Austria and for 16 countries the risk was zero. Overall the risk of RVFV import through ship‐cargo was zero for most of the EU Member States and low for the Netherlands, Spain, Germany and Belgium. [ABSTRACT FROM AUTHOR]

Recently, a new animal virus with the potential to infect humans has been discovered in eastern China, known as Langya I henipavirus i (LayV).[1] This Henipavirus belongs to the Paramyxovirus family containing enveloped, single-stranded RNA. However, recent incidents of a severe acute respiratory syndrome (SARS) coronavirus 2 and Monkeypox virus mutating from animal-to-human toward human-to-human transmission have shown how a zoonotic outbreak may wreak havoc in society leading to fatal consequences. The results indicate that the mole-like mammals may act as "natural reservoirs" for the virus.[[1], [5]] Due to the lack of human-to-human transmission reports till now,[5] the virus does not appear to be particularly contagious and lethal causing authorities unduly concerned. [Extracted from the article]

At completion of Hajj, the Islamic pilgrimage to Makkah, pilgrims give thanks for the blessing, and acceptance, of Hajj, marking the end of the pilgrimage by sacrificing an animal and distributing the sacrificial meat to the poor. With over two million Muslims making Hajj, each Hajj, more than 1.2 million heads of cattle: sheep, goats and camels are slaughtered. Over 16 000 abattoir workers work around the clock to sacrifice and process the cattle in keeping with Islamic law and public health guidelines. Because of their proximity to high densities of cattle and cattle meat, Makkah's abattoir workers are at risk of zoonosis. This was a longitudinal study aimed at determining the risk of some zoonotic diseases among male permanent abattoir workers during Hajj. Specifically, seroprevalence of antigens for Brucella, Crimean–Congo haemorrhagic fever (CCHF), Alkhurma haemorrhagic fever (AHF) and Rift Valley Fever (RVF) were determined, among the study participants. An enrolment questionnaire, and a follow‐up questionnaire, with provision of 10 mL blood for testing 2 days before intense Hajj animal exposure, up to 20 days after intense animal exposure and between 30 and 42 days after Hajj butchering exposures. While working with livestock, study participants were interrogated on hand hygiene and personal protection. Eighty male permanent abattoir workers participated in the study. Majority, 96.25% (n = 77) declared washing their hands with soap and water, most 98.75% (n = 79) never used eye protection, few occupational workers dressed in personal protective clothing or footwear. All workers tested negative for CCHF and RVF, one was positive for AHF and six for Brucella. The risk of some zoonotic infections like Brucella and AHF is low among permanent occupational workers in the slaughtering house in Makkah during Hajj 2013. No serological evidence for CCHF and RVF viruses, even though workers showed low compliance with use of personnel protective equipment. [ABSTRACT FROM AUTHOR]

Rift Valley fever (RVF) is a mosquito‐borne viral zoonosis causing abortions and high mortality among animals, whereas in humans, the disease is usually mild or asymptomatic. In September 2016, the Republic of Niger declared the first RVF outbreak in the northern region of Tahoua near the Malian border. This study describes the outbreak and reports the results of serological and molecular investigations of the human and animal samples collected. Serum samples from both human and animal suspected cases have been confirmed at the Centre de Recherche Médicale et Sanitaire (CERMES) and the Laboratoire Centrale d'Elevage (LABOCEL) public health and animal reference laboratories, respectively. Techniques for biological confirmation were real time reverse transcription polymerase chain reaction (RT‐PCR) and enzyme linked immunosorbent assay (ELISA). Phylogenetic trees were established after genetic sequencing of the small and medium segments of the RVF virus (RVFV) genome. Out of the 399 human samples collected, 17 (4.3%) were confirmed positive for RVFV. Overall, 33 (8.3%) deaths occurred out of which five (29%) were among the 17 confirmed cases. Regarding animals, 45 samples were tested, three of which were RT‐PCR positive and 24 were IgG positive. The phylogenetic analyses showed that the Niger strains clustered with Senegal 2013 and Mauritania 2015 RVFV strains. This first outbreak of RVF was very challenging for public and animal health laboratories in Niger. Besides resulting in human deaths, important loss of cattle has been reported. Therefore, vigilance has to be strengthened emphasising vector control strategies and active surveillance among animals. RVF outbreak in Niger, 2016. The phylogenetic analyses of strains showed similarities with Senegal 2013 and Mauritania 2015 RVFV strains. [ABSTRACT FROM AUTHOR]

Emerging pandemics: Lesson for one-health approach For example Bubonic Plague of 1665, Spanish flu of 1918, SARS-CoV of 2002-2003, H SB 1 sb N SB 1 sb influenza of 2009, Zika pandemics of 2013 and the ongoing COVID-19 pandemic. Till now, holistic systems of integrating human health, animal health and environment-related disciplines have not been implemented. (2018). 1918 Pandemic (H1N1 virus)|Pandemic Influenza (Flu)|CDC. [Extracted from the article]

Abstract: Culex antennatus (Diptera: Culicidae), Anopheles coustani (Diptera: Culicidae) and Anopheles squamosus/cydippis were found to be infected with Rift Valley fever virus (RVFV) during an epidemic that occurred in 2008 and 2009 in Madagascar. To understand the roles played by Cx. antennatus and An. coustani in virus maintenance and transmission, RVFV vector competence was assessed in each species. Mosquito body parts and saliva of mosquitoes that fed on RVFV‐infected blood were tested for RVFV using real‐time quantitative polymerase chain reaction (RT‐qPCR) assays. Overall, viral RNA was detected in body parts and saliva at 5 days post‐infection (d.p.i.) in both species. At 5 d.p.i., infection rates were 12.5% (3/24) and 15.8% (6/38), disseminated infection rates were 100% (3/3) and 100% (6/6), transmission rates were 33.3% (1/3) and 83.3% (5/6), and transmission efficiencies were 4.2% (1/24) and 13.2% (5/38) in Cx. antennatus and An. coustani, respectively. Although RVFV detected in saliva did not propagate on to Vero cells, these results support potential roles for these two mosquito species in the transmission of RVFV. [ABSTRACT FROM AUTHOR]

Rift Valley fever ( RVF) is a mosquito-borne disease caused by the Rift Valley fever virus ( RVFV). Rift Valley fever affects a large number of species, including human, and has severe impact on public health and the economy, especially in African countries. The present study examined the vector competence of three different European mosquito species, Culex pipiens ( Linnaeus, 1758) form molestus (Diptera: Culicidae), Culex pipiens hybrid form and Stegomyia albopicta (= Aedes albopictus) ( Skuse, 1894) (Diptera: Culicidae). Mosquitoes were artificially fed with blood containing RVFV. Infection, disseminated infection and transmission efficiency were evaluated. This is the first study to assess the transmission efficiency of European mosquito species using a virulent RVFV strain. The virus disseminated in Cx. pipiens hybrid form and in S. albopicta. Moreover, infectious viral particles were isolated from saliva of both species, showing their RVFV transmission capacity. The presence of competent Cx. pipiens and S. albopicta in Spain indicates that an autochthonous outbreak of RVF may occur if the virus is introduced. These findings provide information that will help health authorities to set up efficient entomological surveillance and RVFV vector control programmes. [ABSTRACT FROM AUTHOR]

Rift Valley fever (RVF) is a severe mosquito-borne disease affecting humans and domestic ruminants. RVF virus has been reported in most African countries, as well as in the Arabic Peninsula. This paper reviews the different types of socio-economic impact induced by RVF disease and the attempts to evaluate them. Of the 52 papers selected for this review, 13 types of socio-economic impact were identified according to the sector impacted, the level and temporal scale of the impact. RVF has a dramatic impact on producers and livestock industries, affecting public and animal health, food security and the livelihood of the pastoralist communities. RVF also has an impact on international trade and other agro-industries. The risk of introducing RVF into disease-free countries via the importation of an infected animal or mosquito is real, and the consequent restriction of access to export markets may induce dramatic economic consequences for national and local economies. Despite the important threat of RVF, few studies have been conducted to assess the socio-economic impact of the disease. The 17 studies identified for quantitative analysis in this review relied only on partial cost analysis, with limited reference to mid- and long-term impact, public health or risk mitigation measures. However, the estimated impacts were high (ranging from $5 to $470 million USD losses). To reduce the impact of RVF, early detection and rapid response should be implemented. Comprehensive disease impact studies are required to provide decision-makers with science-based information on the best intervention measure to implement ensuring efficient resource allocation. Through the analysis of RVF socio-economic impact, this scoping study proposes insights into the mechanisms underpinning its often-underestimated importance. This study highlights the need for comparative socio-economic studies to help decision-makers with their choices related to RVF disease management. [ABSTRACT FROM AUTHOR]

OBJECTIVE To identify risk factors for human Rift Valley fever virus (RVFV) infection. METHODS A systematic review identified 17 articles reporting on 16 studies examining risk factors for RVFV. Pooled odds ratios (pOR) were calculated for exposures examined in four or more studies. results Being male [pOR = 1.4 (1.0, 1.8)], contact with aborted animal tissue [pOR = 3.4 (1.6, 7.3)], birthing an animal [pOR = 3.2 (2.4, 4.2)], skinning an animal [pOR = 2.5 (1.9, 3.2)], slaughtering an animal [pOR = 2.4 (1.4, 4.1)] and drinking raw milk [pOR = 1.8 (1.2, 2.6)] were significantly associated with RVF infection after meta-analysis. Other potential risk factors include sheltering animals in the home and milking an animal, which may both involve contact with animal body fluids. CONCLUSIONS Based on the identified risk factors, use of personal protective equipment and disinfectants by animal handlers may help reduce RVFV transmission during outbreaks. Milk pasteurisation and other possible preventive methods require further investigation. [ABSTRACT FROM AUTHOR]

Two species of arbovirus vector, Culex torrentium and Culex pipiens (Diptera: Culicidae), occur in several European countries, but difficulties in their accurate identification and discrimination have hampered both detailed and large-scale distribution and abundance studies. Using a molecular identification method, we identified to species 2559 larvae of Cx. pipiens/torrentium collected from 138 sites in 13 European countries ranging from Scandinavia to the Mediterranean coast. In addition, samples of 1712 males of Cx. pipiens/torrentium collected at several sites in the Czech Republic were identified to species based on the morphology of their hypopygia. We found that the two species occur together in large areas of Europe, and that Cx. torrentium dominates in northern Europe and Cx. pipiens dominates south of the Alps. The transition in dominance occurs in central Europe, where both species are roughly equally common. There was a strong correlation between the length of the growing season at different sites and occurrences of the two species. As the growing season increases, the proportion and detection of Cx. torrentium decrease, whereas those of Cx. pipiens increase. The present findings have important consequences for the interpretation of the results of studies on major enzootic and link-vectors of mosquito-borne bird-associated viruses (i.e. Sindbis, West Nile and Usutu viruses), especially in central Europe and Scandinavia. [ABSTRACT FROM AUTHOR]

Rift Valley Fever (RVF) virus is a mosquito-born pathogen that infects livestock but it also has the capability to infect humans through direct or indirect contact with blood or organs of infected animals and by bites from infected mosquitos. The economic and social cost of the disease to rural populations can lead to a cascade of negative effects on the sustainability of animal and human populations. Vaccines exist to protect against this disease. Through a compartment model depicting the interactions leading to the spread of RVF in Aedes and Culex mosquitos and a livestock population, an optimal control problem is developed to minimize the number of vaccinated livestock at the final time while minimizing the negative effects of the infected Aedes and Culex mosquitos and the cost of the vaccination process. The unique optimal vaccination strategy is produced for given high transmission parameters and numerical results portray that vaccination depends on the level of effectiveness of the protocol. [ABSTRACT FROM AUTHOR]

Rift Valley fever virus (RVFV) is an arbovirus that causes significant morbidity and mortality in both humans and livestock. With increased world travel and the threat of bioterrorism, there is a real risk of RVFV spreading to naïve geographical areas ( Trans. R. Soc. Trop. Med. Hyg., 73, 1979, 618; MMWR Morb. Mortal. Wkly Rep., 49, 2000, 905). The introduction of RVFV would cause critical public health, agricultural and economic damage. Despite the clear need for an efficacious vaccine, there are no United States (US) Food and Drug Administration or US Department of Agriculture approved vaccines against RVFV. To address this need, a virus-like particle (VLP)-based vaccine candidate was developed. First, a non-replicating chimeric RVF VLP vaccine candidate was generated that protected mice and rats against a lethal RVFV challenge. This was followed by the development and optimization of conditions for production of RVF VLPs in insect and mammalian cells. Immunological studies demonstrated that VLP-based vaccine candidates elicit both humoral and cellular immune responses. Subsequent challenge studies using a lethal wild-type RVFV strain under high-containment conditions showed that RVF VLP vaccine candidates can completely protect mice and rats. [ABSTRACT FROM AUTHOR]

The article focuses on the etiology and epidemiology of the Rift Valley Fever Virus (RVFV) in Spain. It mentions that the RVFV is a mosquito-borne virua and a member of the Phlebovirus that affects mainly the ruminant species. It adds that the RVF is considered endemic in the sub-Saharan African countries associated with periods of heavy rainfall and flooding. It also cites the risk for Spain as it may be associated with transportation of infected vectors on the wind.

Rift Valley fever virus (RVFV), which belongs to the genus Phlebovirus, family Bunyaviridae, is a negative-stranded RNA virus carrying a single-stranded, tripartite RNA genome. RVFV is an important zoonotic pathogen transmitted by mosquitoes and causes large outbreaks among ruminants and humans in Africa and the Arabian Peninsula. Human patients develop an acute febrile illness, followed by a fatal hemorrhagic fever, encephalitis, or ocular diseases. A viral nonstructural protein, NSs, is a major viral virulence factor. Past studies showed that NSs suppresses the transcription of host mRNAs, including interferon-β mRNAs. Here we demonstrated that the NSs protein induced post-transcriptional downregulation of dsRNA-dependent protein kinase (PKR), to prevent phosphorylation of eIF2α and promoted viral translation in infected cells. These two biological activities of the NSs most probably have a synergistic effect in suppressing host innate immune functions and facilitate efficient viral replication in infected mammalian hosts. [ABSTRACT FROM AUTHOR]

The article discusses issues discussed in the international disease monitoring report for January to March 2007, prepared by the Dept. for Environment, Food and Rural Affairs' Food and Farming Group, International Animal Health. These include cases of bluetongue detected in north-west Europe, emergency vaccination of pigs in Romania to control classical swine fever, outbreaks of pathogenic avian influenza in Hungary and Great Britain, and Rift Valley fever confirmed in Kenya and Tanzania.

Rift Valley fever is an endemic vector-borne disease in West Africa, which mainly affects domestic ruminants and occasionally humans. The aetiological mechanisms of its endemicity remain under debate. We used a simple spatially explicit model to assess the possibility of endemicity without wild animals providing a permanent virus reservoir. Our model takes into account the vertical transmission in some mosquito species, the rainfall-driven emergence of their eggs and local and distant contacts because of herd migration. Endemicity without such a permanent virus reservoir would be impossible in a single site except when there is a strictly periodic rainfall pattern; but it would be possible when there are herd movements and sufficient inter-site variability in rainfall, which drives mosquito emergence. [ABSTRACT FROM AUTHOR]

Following an outbreak of Rift Valley fever (RVF) in south-eastern Mauritania during 1998, entomological investigations were conducted for 2 years in the affected parts of Senegal and Mauritania, spanning the Sénégal River basin. A total of 92 787 mosquitoes (Diptera: Culicidae), belonging to 10 genera and 41 species, were captured in light traps. In Senegal,Culex poicilipes(41%) andMansonia uniformis(39%) were the most abundant species caught, whereasAedes vexans(77%) andCx. poicilipes(15%) predominated in Mauritania. RVF virus was isolated from 63 pools ofCx.poicilipes: 36 from Senegal in 1998 and 27 from Mauritania in 1999. These results are the first field evidence ofCx. poicilipesnaturally infected with RVFV, and the first isolations of this virus from mosquitoes in Mauritania– the main West African epidemic and epizootic area. Additional arbovirus isolates comprised 25 strains of Bagaza (BAG) fromAedes fowleri,Culex neaveiandCx. poicilipes; 67 Sanar (ArD 66707) fromCx. poicilipes; 51 Wesselsbron (WSL) fromAe. vexansand 30 strains of West Nile (WN) fromMa. uniformis, showing differential specific virus–vector associations in the circulation activity of these five arboviruses. [ABSTRACT FROM AUTHOR]

Rift Valley Fever (RVF) is a growing health problem in West Africa. In northern Senegal, the candidate vectors of this arbovirosis are Aedes ( Aedimorphus) vexans Meigen and Culex ( Culex) poicilipes Theobald (Diptera: Culicidae). Domestic ruminants are the reservoirs of the virus . A study was undertaken during the 2002 rainy season to assess spatial and temporal variations in exposure to mosquito bites in sheep herds, and to evaluate the possible consequences on the risk of RVF transmission to sheep. Mosquitoes were collected with sheep-baited traps. The number of Ae. vexans females (the predominant species during the 2002 rainy season) trapped per trap-night was the dependent variable in statistical analyses. The trapping periods were divided into six series of two to five consecutive days, from July to November 2002. Three temporary ponds were selected according to their ecological features: depth, bank slope, size and vegetation cover. Traps were laid on the pond bank and in the nearest available compound, close to the sheep night pen. Data were analysed using mixed-effects Poisson models. The explanatory variables were the trapping period, the pond, and the capture site. The exposure to mosquito bites varied according to the pond type, suggesting that the risk of transmission was spatially heterogeneous. However, there was no obvious trend in transmission risk due to the effect of the distance from the compound to the pond. The period with the highest exposure was in October, i.e. when transhumant herds left the Ferlo to relocate to their dry-season settlement. It is thus hypothesized that transhumance, the seasonal movements of herds, plays a significant role in the dissemination of RVF virus in the region. [ABSTRACT FROM AUTHOR]

Abstract. In mid-September 2000, Rift Valley fever (RVF) virus was diagnosed as the cause of infection in humans and livestock in Jizan Region, Saudi Arabia. This is the first time that this arbovirus has been found outside Africa and Madagascar. Collections of mosquitoes (Diptera: Culicidae) were therefore undertaken (from 25 September to 10 October) at eight sites during the epidemic to obtain mosquitoes for attempted RVF virus isolation. Among 23 699 mosquito females tested, isolations of RVF virus were made from six of 15 428 Culex (Culex ) tritaeniorhynchus Giles and from seven of 8091 Aedes vexans arabiensis Patton. Minimum mosquito infection rates per 1000 at sites with infected mosquitoes were 0.3–13.8 Cx. tritaeniorhynchus and 1.94–9.03 Ae. v. arabiensis . Viral activity moved northwards as collecting was in progress and collectors ‘caught up’ with the virus at the two most northerly sites on the last two trapping evenings. Other species occurred in small numbers and were identified but not tested. Both Cx. tritaeniorhynchus and Ae. v. arabiensis were susceptible to RVF virus and transmitted between hamsters, and an additional quantitative test with Cx. tritaeniorhynchus showed that 71–73% of mosquitoes became infected after ingesting 6.9–7.9 log10 FFU/mL of virus; transmission rates were 10% (post-infection day 14) and 26% (post-infection day 20). It was concluded that both species were vectors on grounds of abundance, distribution, preference for humans and sheep, the virus isolations and vector competence tests. [ABSTRACT FROM AUTHOR]

After the Rift valley fever (RVF) epidemic of 1987 in the Senegal River Basin, RVF surveillance based on serosurveys has been conducted for 10 years. Serum samples were obtained from 1336 persons and from sheep and goats in selected areas, and these were tested for IgG/IgM RVF antibodies by ELISA. After a period of regular decrease in RVF prevalence in domestic animals until 1993, an epizootic was observed in all herds in 1994-95 with increases in IgM levels and abortions. During the same period, no human cases or RVF IgM were detected. The RVF IgG prevalence significantly correlated with date of birth: children born after 1987 have a low prevalence (5%) in clear contrast to the older population (25.3%) in Podor district. A retrospective analysis of rainfall and RVF prevalence in small domestic animals over the last 10 years showed that the re-emergence correlated with heavy rainfall. A general analysis of the risk of re-emergence and the efficiency of this RVF surveillance system are presented. [ABSTRACT FROM AUTHOR]

A new myxosporean, Triangula percae sp. nov., (Myxozoa: Ortholineidae) from the brain of redfin perch, Perca fluviatilis L., is described. Spinal curvatures are prevalent in many perch populations in Victoria, Australia. Triangula percae infection was detected in all perch displaying spinal curvatures and in 67% of normal perch from Lake Nillahcootie in north east Victoria. Perch populations exhibiting spinal curvatures in several other waterways were also infected with Triangula percae but the infection was absent in one population which was apparently normal. Triangula percae infection is, thus, considered to be the cause of a proportion of the spinal curvatures. Certain fish surviving outbreaks of epizootic haematopoietic necrosis virus (EHNV) also developed spinal curvatures, which may have been due to viral infection of the central nervous system. [ABSTRACT FROM AUTHOR]

During a toxicology study in cynomolgus (long-tailed or crab eating) monkeys (Macaca fascicularis), a randomly distributed incidence of significantly increased hepatic enzyme activity was observed. Premedication hepatic enzyme activity in all monkeys of this study was normal, but increased alanine aminotransferase (ALT) activity was found in 4 of the 24 animals 2 weeks afar initiation of the study and in 10 of 24 at 4 weeks. A drug-related effect was considered unlikely initially because the increases were not dose-related, and a 3-year review of 655 cynomolgus monkeys revealed a 15–20% incidence of increased hepatic enzyme activity. Good correlation was subsequently established between increased hepatic enzyme activity, active hepatitis A virus (HAV) infection, and histomorphologic confirmation of hepatitis (chronic periportal inflammation). Follow-up viral serodiagnostic screening of resident macaques revealed an overall incidence of anti-HAV IgG in 80% (155/193) of cynomolgus and in 70% (14/20) of rhesus monkeys. Serial screening demonstrated that several initially negative monkeys became seropositire for anti-HAV IgG, and a few acquired active infection (anti-HAV IgM). Among newly acquired cynomolgus monkeys, 2.5% (2/80) had an acute HAV infection, and 35% (28/80) eventually tested positive for anti-HAV IgG while quarantined in the primate facility. The characterization of an enzootic HAY infection in incoming monkeys posed a significant risk for the primate colony and handlers. Rigorous sanitation, isolation, and quarantine procedures, including personnel training and additional protective clothing for personnel working in the primate colony, reduced the potential for transmission and arrested the outbreak. Experimenters should be cautious in ascribing toxicity to a test article based solely on increased hepatic enzyme activity associated with chronic periportal inflammation. [ABSTRACT FROM AUTHOR]