Dead or alive: animal sampling during Ebola hemorrhagic fever outbreaks in humans

There are currently no widely accepted animal surveillance guidelines for human Ebola hemorrhagic fever (EHF) outbreak investigations to identify potential sources of Ebolavirus (EBOV) spillover into humans and other animals. Animal field surveillance during and following an outbreak has several purposes, from helping identify the specific animal source of a human case to guiding control activities by describing the spatial and temporal distribution of wild circulating EBOV, informing public health efforts, and contributing to broader EHF research questions. Since 1976, researchers have sampled over 10,000 individual vertebrates from areas associated with human EHF outbreaks and tested for EBOV or antibodies. Using field surveillance data associated with EHF outbreaks, this review provides guidance on animal sampling for resource-limited outbreak situations, target species, and in some cases which diagnostics should be prioritized to rapidly assess the presence of EBOV in animal reservoirs. In brief, EBOV detection was 32.7% (18/55) for carcasses (animals found dead) and 0.2% (13/5309) for live captured animals. Our review indicates that for the purposes of identifying potential sources of transmission from animals to humans and isolating suspected virus in an animal in outbreak situations, (1) surveillance of free-ranging non-human primate mortality and morbidity should be a priority, (2) any wildlife morbidity or mortality events should be investigated and may hold the most promise for locating virus or viral genome sequences, (3) surveillance of some bat species is worthwhile to isolate and detect evidence of exposure, and (4) morbidity, mortality, and serology studies of domestic animals should prioritize dogs and pigs and include testing for virus and previous exposure

Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats

In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security

Dead or alive: animal sampling during Ebola hemorrhagic fever outbreaks in humans.

There are currently no widely accepted animal surveillance guidelines for human Ebola hemorrhagic fever (EHF) outbreak investigations to identify potential sources of Ebolavirus (EBOV) spillover into humans and other animals. Animal field surveillance during and following an outbreak has several purposes, from helping identify the specific animal source of a human case to guiding control activities by describing the spatial and temporal distribution of wild circulating EBOV, informing public health efforts, and contributing to broader EHF research questions. Since 1976, researchers have sampled over 10,000 individual vertebrates from areas associated with human EHF outbreaks and tested for EBOV or antibodies. Using field surveillance data associated with EHF outbreaks, this review provides guidance on animal sampling for resource-limited outbreak situations, target species, and in some cases which diagnostics should be prioritized to rapidly assess the presence of EBOV in animal reservoirs. In brief, EBOV detection was 32.7% (18/55) for carcasses (animals found dead) and 0.2% (13/5309) for live captured animals. Our review indicates that for the purposes of identifying potential sources of transmission from animals to humans and isolating suspected virus in an animal in outbreak situations, (1) surveillance of free-ranging non-human primate mortality and morbidity should be a priority, (2) any wildlife morbidity or mortality events should be investigated and may hold the most promise for locating virus or viral genome sequences, (3) surveillance of some bat species is worthwhile to isolate and detect evidence of exposure, and (4) morbidity, mortality, and serology studies of domestic animals should prioritize dogs and pigs and include testing for virus and previous exposure

Simian homologues of human herpesviruses and implications for novel viral introduction to free‐living mountain gorillas

The endangered mountain gorilla (Gorilla beringei beringei) in Rwanda, Uganda, and the Democratic Republic of Congo is frequently in contact with humans through tourism, research activities, and illegal entry of people into protected gorilla habitat. Herpesviruses, which are ubiquitous in primates, have the potential to be shared in any setting where humans and gorillas share habitat. Based on serological findings and clinical observations of orofacial ulcerated lesions resembling herpetic lesions, an alpha-herpesvirus resembling human herpes simplex virus type 1 (HSV-1) has long been suspected to be present in human-habituated mountain gorillas in the wild. While the etiology of orofacial lesions in the wild has not been confirmed, HSV-1 has been suspected in captively-housed mountain gorillas and confirmed in a co-housed confiscated Grauer's gorilla (Gorilla beringei graueri). To better characterize herpesviruses infecting mountain gorillas and to determine the presence/absence of HSV-1 in the free-living population, we conducted a population-wide survey to test for the presence of orally shed herpesviruses. DNA was extracted from discarded chewed plants collected from 294 individuals from 26 groups, and samples were screened by polymerase chain reaction using pan-herpesvirus and HSV-1-specific assays. We found no evidence that human herpesviruses had infected free-ranging mountain gorillas. However, we found gorilla-specific homologs to human herpesviruses, including cytomegaloviruses (GbbCMV-1 and 2), a lymphocryptovirus (GbbLCV-1), and a new rhadinovirus (GbbRHV-1) with similar characteristics (i.e., timing of primary infection, shedding in multiple age groups, and potential modes of transmission) to their human counterparts, human cytomegalovirus, Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus, respectively

Mountain gorilla lymphocryptovirus has Epstein-Barr virus-like epidemiology and pathology in infants.

Epstein-Barr virus (EBV) infects greater than 90% of humans, is recognized as a significant comorbidity with HIV/AIDS, and is an etiologic agent for some human cancers. The critically endangered mountain gorilla population was suspected of infection with an EBV-like virus based on serology and infant histopathology similar to pulmonary reactive lymphoid hyperplasia (PRLH), a condition associated with EBV in HIV-infected children. To further examine the presence of EBV or an EBV-like virus in mountain gorillas, we conducted the first population-wide survey of oral samples for an EBV-like virus in a nonhuman great ape. We discovered that mountain gorillas are widely infected (n = 143/332) with a specific strain of lymphocryptovirus 1 (GbbLCV-1). Fifty-two percent of infant mountain gorillas were orally shedding GbbLCV-1, suggesting primary infection during this stage of life, similar to what is seen in humans in less developed countries. We then identified GbbLCV-1 in post-mortem infant lung tissues demonstrating histopathological lesions consistent with PRLH, suggesting primary infection with GbbLCV-1 is associated with PRLH in infants. Together, our findings demonstrate that mountain gorilla's infection with GbbLCV-1 could provide valuable information for human disease in a natural great ape setting and have potential conservation implications in this critically endangered species

Optimization of a Novel Non-invasive Oral Sampling Technique for Zoonotic Pathogen Surveillance in Nonhuman Primates.

Free-ranging nonhuman primates are frequent sources of zoonotic pathogens due to their physiologic similarity and in many tropical regions, close contact with humans. Many high-risk disease transmission interfaces have not been monitored for zoonotic pathogens due to difficulties inherent to invasive sampling of free-ranging wildlife. Non-invasive surveillance of nonhuman primates for pathogens with high potential for spillover into humans is therefore critical for understanding disease ecology of existing zoonotic pathogen burdens and identifying communities where zoonotic diseases are likely to emerge in the future. We developed a non-invasive oral sampling technique using ropes distributed to nonhuman primates to target viruses shed in the oral cavity, which through bite wounds and discarded food, could be transmitted to people. Optimization was performed by testing paired rope and oral swabs from laboratory colony rhesus macaques for rhesus cytomegalovirus (RhCMV) and simian foamy virus (SFV) and implementing the technique with free-ranging terrestrial and arboreal nonhuman primate species in Uganda and Nepal. Both ubiquitous DNA and RNA viruses, RhCMV and SFV, were detected in oral samples collected from ropes distributed to laboratory colony macaques and SFV was detected in free-ranging macaques and olive baboons. Our study describes a technique that can be used for disease surveillance in free-ranging nonhuman primates and, potentially, other wildlife species when invasive sampling techniques may not be feasible

Optimization of a Novel Non-invasive Oral Sampling Technique for Zoonotic Pathogen Surveillance in Nonhuman Primates

<div><p>Free-ranging nonhuman primates are frequent sources of zoonotic pathogens due to their physiologic similarity and in many tropical regions, close contact with humans. Many high-risk disease transmission interfaces have not been monitored for zoonotic pathogens due to difficulties inherent to invasive sampling of free-ranging wildlife. Non-invasive surveillance of nonhuman primates for pathogens with high potential for spillover into humans is therefore critical for understanding disease ecology of existing zoonotic pathogen burdens and identifying communities where zoonotic diseases are likely to emerge in the future. We developed a non-invasive oral sampling technique using ropes distributed to nonhuman primates to target viruses shed in the oral cavity, which through bite wounds and discarded food, could be transmitted to people. Optimization was performed by testing paired rope and oral swabs from laboratory colony rhesus macaques for rhesus cytomegalovirus (RhCMV) and simian foamy virus (SFV) and implementing the technique with free-ranging terrestrial and arboreal nonhuman primate species in Uganda and Nepal. Both ubiquitous DNA and RNA viruses, RhCMV and SFV, were detected in oral samples collected from ropes distributed to laboratory colony macaques and SFV was detected in free-ranging macaques and olive baboons. Our study describes a technique that can be used for disease surveillance in free-ranging nonhuman primates and, potentially, other wildlife species when invasive sampling techniques may not be feasible.</p></div

Estimated sensitivity and specificity of rope and swab sample collection techniques for the detection of rhesus cytomegalovirus and simian foamy virus based on a Bayesian analysis in the absence of a gold standard.

<p>¹RhCMV, rhesus cytomegalovirus; SFV, simian foamy virus.</p><p>²Sensitivity and specificity were estimated by using a “two dependent test, one population, no gold standard” Bayesian model.</p><p>Estimated sensitivity and specificity of rope and swab sample collection techniques for the detection of rhesus cytomegalovirus and simian foamy virus based on a Bayesian analysis in the absence of a gold standard.</p

Agreement of detection of rhesus cytomegalovirus and simian foamy virus in oral samples collected from ropes and swabs from laboratory colony rhesus macaques.

<p>¹RhCMV, rhesus cytomegalovirus; SFV, simian foamy virus.</p><p>²The percentage of samples with negative test results from both swab and rope.</p><p>³The percentage of samples with positive results from both swab and ropes.</p><p>⁴Prevalence-adjusted bias-adjusted kappa.</p><p>Agreement of detection of rhesus cytomegalovirus and simian foamy virus in oral samples collected from ropes and swabs from laboratory colony rhesus macaques.</p

Rope materials tested for the collection of oral samples from nonhuman primates.

<p>Left: Nylon oral swab rope, middle: cotton rope, right: nylon rope. (Photo by N. Walker).</p