Background. Trypanosoma is a genus of unicellular parasitic flagellate protozoa. Trypanosoma brucei species and Trypanosoma cruzi are the major agents of human trypanosomiasis; other Trypanosoma ...species can cause human disease, but are rare. In March 2015, a 38-year-old woman presented to a healthcare facility in southern Vietnam with fever, headache, and arthralgia. Microscopic examination of blood revealed infection with Trypanosoma. Methods. Microscopic observation, polymerase chain reaction (PCR) amplification of blood samples, and serological testing were performed to identify the infecting species. The patient's blood was screened for the trypanocidal protein apolipoprotein L1 (APOL1), and a field investigation was performed to identify the zoonotic source. Results. PCR amplification and serological testing identified the infecting species as Trypanosoma evansi. Despite relapsing 6 weeks after completing amphotericin B therapy, the patient made a complete recovery after 5 weeks of suramin. The patient was found to have 2 wild-type APOL1 alleles and a normal serum APOL1 concentration. After responsive animal sampling in the presumed location of exposure, cattle and/or buffalo were determined to be the most likely source of the infection, with 14 of 30 (47%) animal blood samples testing PCR positive for T. evansi. Conclusions. We report the first laboratory-confirmed case of T. evansi in a previously healthy individual without APOL1 deficiency, potentially contracted via a wound while butchering raw beef, and successfully treated with suramin. A linked epidemiological investigation revealed widespread and previously unidentified burden of T. evansi in local cattle, highlighting the need for surveillance of this infection in animals and the possibility of further human cases.
Nontyphoidal
(NTS), particularly
serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in ...sub-Saharan Africa. In contrast,
Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in
Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal
Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of
Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of
Typhimurium (serovar I:4,5,12:i:- sequence type 34 ST34) has been introduced into Vietnam, reacquired a phase 2 flagellum, and acquired an IncHI2 multidrug-resistant plasmid. Notably, these novel biphasic ST34
Typhimurium variants were significantly associated with iNTS in Vietnamese HIV-infected patients. Our study represents the first characterization of novel iNTS organisms isolated outside sub-Saharan Africa and outlines a new pathway for the emergence of alternative
variants into susceptible human populations.
Typhimurium is a major diarrheal pathogen and associated with invasive nontyphoid
(iNTS) disease in vulnerable populations. We present the first characterization of iNTS organisms in Southeast Asia and describe a different evolutionary trajectory from that of organisms causing iNTS in sub-Saharan Africa. In Vietnam, the globally distributed monophasic variant of
Typhimurium, the serovar I:4,5,12:i:- ST34 clone, has reacquired a phase 2 flagellum and gained a multidrug-resistant plasmid to become associated with iNTS disease in HIV-infected patients. We document distinct communities of
Typhimurium and I:4,5,12:i:- in animals and humans in Vietnam, despite the greater mixing of these host populations here. These data highlight the importance of whole-genome sequencing surveillance in a One Health context in understanding the evolution and spread of resistant bacterial infections.
There is still limited information on the diversity of viruses co-circulating in humans and animals. Here, we report data obtained from a large field collection of enteric samples taken from humans, ...pigs, rodents and other mammal hosts in Vietnam between 2012 and 2016. Each of 2100 stool or rectal swab samples was subjected to virally-enriched agnostic metagenomic sequencing; the short read sequence data are accessible from the European Nucleotide Archive (ENA). We link the sequence data to metadata on host type and demography and geographic location, distinguishing hospital patients, members of a cohort identified as a high risk of zoonotic infections (e.g. abattoir workers, rat traders) and animals. These data are suitable for further studies of virus diversity and virus discovery in humans and animals from Vietnam and to identify viruses found in multiple hosts that are potentially zoonotic.
Despite the global zoonotic disease burden, the underlying exposures that drive zoonotic disease emergence are not understood. Here, we aimed to assess exposures to potential sources of zoonotic ...disease and investigate the demographics, attitudes, and behavior of individuals with sustained occupational animal contact in Vietnam. We recruited 581 animal workers (animal-raising farmers, slaughterers, animal health workers, and rat traders) and their families in southern and central Vietnam into a cohort. Cohort members were followed for 3 years and interviewed annually regarding (1) demography and attitudes regarding zoonotic disease, (2) medical history, (3) specific exposures to potential zoonotic infection sources, and (4) socioeconomic status. Interview information over the 3 years was combined and analyzed as cross-sectional data. Of the 297 cohort members interviewed, the majority (79.8%; 237/297) reported raising livestock; almost all (99.6%; 236/237) reported being routinely exposed to domestic animals, and more than a quarter (28.7%; 68/237) were exposed to exotic animals. Overall, 70% (208/297) reported slaughtering exotic animals; almost all (99.5%; 207/208) reported consuming such animals. The consumption of raw blood and meat was common (24.6%; 73/297 and 37%; 110/297, respectively). Over half (58.6%; 174/297) reported recent occupational animal-induced injuries that caused bleeding; the use of personal protective equipment (PPE) was limited. Our work demonstrates that individuals working with animals in Vietnam are exposed to a wide range of species, and there are limited procedures for reducing potential zoonotic disease exposures. We advocate better education, improved animal security, and enforced legislation of PPE for those with occupational animal exposure in Vietnam.
The effect of newly emerging or re-emerging infectious diseases of zoonotic origin in human populations can be potentially catastrophic, and large-scale investigations of such diseases are highly ...challenging. The monitoring of emergence events is subject to ascertainment bias, whether at the level of species discovery, emerging disease events, or disease outbreaks in human populations. Disease surveillance is generally performed post hoc, driven by a response to recent events and by the availability of detection and identification technologies. Additionally, the inventory of pathogens that exist in mammalian and other reservoirs is incomplete, and identifying those with the potential to cause disease in humans is rarely possible in advance. A major step in understanding the burden and diversity of zoonotic infections, the local behavioral and demographic risks of infection, and the risk of emergence of these pathogens in human populations is to establish surveillance networks in populations that maintain regular contact with diverse animal populations, and to simultaneously characterize pathogen diversity in human and animal populations. Vietnam has been an epicenter of disease emergence over the last decade, and practices at the human/animal interface may facilitate the likelihood of spillover of zoonotic pathogens into humans. To tackle the scientific issues surrounding the origins and emergence of zoonotic infections in Vietnam, we have established The Vietnam Initiative on Zoonotic Infections (VIZIONS). This countrywide project, in which several international institutions collaborate with Vietnamese organizations, is combining clinical data, epidemiology, high-throughput sequencing, and social sciences to address relevant one-health questions. Here, we describe the primary aims of the project, the infrastructure established to address our scientific questions, and the current status of the project. Our principal objective is to develop an integrated approach to the surveillance of pathogens circulating in both human and animal populations and assess how frequently they are exchanged. This infrastructure will facilitate systematic investigations of pathogen ecology and evolution, enhance understanding of viral cross-species transmission events, and identify relevant risk factors and drivers of zoonotic disease emergence.
In the Mekong Delta in southern Vietnam, rats are commonly traded in wet markets and sold live for food consumption. We investigated seroprevalence to selected groups of rodent-borne viruses among ...human populations with high levels of animal exposure and among co-located rodent populations. The indirect fluorescence antibody test (IFAT) was used to determine seropositivity to representative reference strains of hantaviruses (Dobrava virus DOBV, Seoul virus SEOV), cowpox virus, arenaviruses (lymphocytic choriomeningitis virus LCMV), flaviviruses (tick-borne encephalitis virus TBEV), and rodent parechoviruses (Ljungan virus), using sera from 245 humans living in Dong Thap Province and 275 rodents representing the five common rodent species sold in wet markets and present in peridomestic and farm settings. Combined seropositivity to DOBV and SEOV among the rodents and humans was 6.9% (19/275) and 3.7% (9/245), respectively; 1.1% (3/275) and 4.5% (11/245) to cowpox virus; 5.4% (15/275) and 47.3% (116/245) for TBEV; and exposure to Ljungan virus was 18.8% (46/245) in humans, but 0% in rodents. Very little seroreactivity was observed to LCMV in either rodents (1/275, 0.4%) or humans (2/245, 0.8%). Molecular screening of rodent liver tissues using consensus primers for flaviviruses did not yield any amplicons, whereas molecular screening of rodent lung tissues for hantavirus yielded one hantavirus sequence (SEOV). In summary, these results indicate low to moderate levels of endemic hantavirus circulation, possible circulation of a flavivirus in rodent reservoirs, and the first available data on human exposures to parechoviruses in Vietnam. Although the current evidence suggests only limited exposure of humans to known rodent-borne diseases, further research is warranted to assess public health implications of the rodent trade.
Coordinated and synchronous surveillance for zoonotic viruses in both human clinical cases and animal reservoirs provides an opportunity to identify interspecies virus movement. Rotavirus (RV) is an ...important cause of viral gastroenteritis in humans and animals. In this study, we document the RV diversity within co-located humans and animals sampled from the Mekong delta region of Vietnam using a primer-independent, agnostic, deep sequencing approach. A total of 296 stool samples (146 from diarrhoeal human patients and 150 from pigs living in the same geographical region) were directly sequenced, generating the genomic sequences of sixty human rotaviruses (all group A) and thirty-one porcine rotaviruses (thirteen group A, seven group B, six group C, and five group H). Phylogenetic analyses showed the co-circulation of multiple distinct RV group A (RVA) genotypes/strains, many of which were divergent from the strain components of licensed RVA vaccines, as well as considerable virus diversity in pigs including full genomes of rotaviruses in groups B, C, and H, none of which have been previously reported in Vietnam. Furthermore, the detection of an atypical RVA genotype constellation (G4-P6-I1-R1-C1-M1-A8-N1-T7-E1-H1) in a human patient and a pig from the same region provides some evidence for a zoonotic event.
Emerging infectious disease surveillance in human and animal populations is a global health imperative and represents an enormous challenge to government authorities, particularly in resource-limited ...settings (Keusch 2009; King et al. 2006). In response to complex threats posed by emerging zoonotic infectious diseases (diseases transmitted from animals to humans), a new paradigm for health research has developed: the One Health approach. The One Health concept is based on core principles of systems thinking, transdisciplinarity, multi-stakeholder participation, equity, sustainability and 'knowledge-to-action' (Charron 2011) and attempts to address the interdependencies of human and animal health by promoting research that considers socioeconomic, cultural and environmental factors. Despite widespread agreement on the need for coordinated surveillance activities that unite public health and animal health objectives (AVMA 2008), there remains little consensus on what comprises the One Health research agenda and relatively few examples of ongoing surveillance that utilise expertise from both human and animal health sectors.
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