Climate-driven marmot-plague dynamics in Mongolia and China.

The incidence of plague has rebounded in the Americas, Asia, and Africa alongside rapid globalization and climate change. Previous studies have shown local climate to have significant nonlinear effects on plague dynamics among rodent communities. We analyzed an 18-year database of plague, spanning 1998 to 2015, in the foci of Mongolia and China to trace the associations between marmot plague and climate factors. Our results suggested a density-dependent effect of precipitation and a geographic location-dependent effect of temperature on marmot plague. That is, a significantly positive relationship was evident between risk of plague and precipitation only when the marmot density exceeded a certain threshold. The geographical heterogeneity of the temperature effect and the contrasting slopes of influence for the Qinghai-Tibet Plateau (QTP) and other regions in the study (nQTP) were primarily related to diversity of climate and landscape types.

Applying next generation sequencing to detect tick-pathogens in Dermacentor nuttalli, Ixodes persulcatus, and Hyalomma asiaticum collected from Mongolia.

Ticks and tick-borne diseases represent major threats to the public health of the Mongolian population, of which an estimated 26% live a traditional nomadic pastoralist lifestyle that puts them at increased risk for exposure. Ticks were collected by dragging and removal from livestock in Khentii, Selenge, Tuv, and Umnugovi aimags (provinces) during March-May 2020. Using next-generation sequencing (NGS) with confirmatory PCR and DNA sequencing, we sought to characterize the microbial species present in Dermacentor nuttalli (n = 98), Hyalomma asiaticum (n = 38), and Ixodes persulcatus (n = 72) tick pools. Rickettsia spp. were detected in 90.4% of tick pools, with Khentii, Selenge, and Tuv tick pools all having 100% pool positivity. Coxiella spp. were detected at an overall pool positivity rate of 60%, while Francisella spp. were detected in 20% of pools and Borrelia spp. detected in 13% of pools. Additional confirmatory testing for Rickettsia-positive pools demonstrated Rickettsia raoultii (n = 105), Candidatus Rickettsia tarasevichiae (n = 65) and R. slovaca/R. sibirica (n = 2), as well as the first report of Candidatus Rickettsia jingxinensis (n = 1) in Mongolia. For Coxiella spp. reads, most samples were identified as a Coxiella endosymbiont (n = 117), although Coxiella burnetii was detected in eight pools collected in Umnugovi. Borrelia species that were identified include Borrelia burgdorferi sensu lato (n = 3), B. garinii (n = 2), B. miyamotoi (n = 16), and B. afzelii (n = 3). All Francisella spp. reads were identified as Francisella endosymbiont species. Our findings emphasize the utility of NGS to provide baseline data across multiple tick-borne pathogen groups, which in turn can be used to inform health policy, determine regions for expanded surveillance, and guide risk mitigation strategies.

Metagenomic profiles of Dermacentor tick pathogens from across Mongolia, using next generation sequencing.

Tick-borne diseases are a major public health concern in Mongolia. Nomadic pastoralists, which make up ~ 26% of Mongolia's population, are at an increased risk of both tick bite exposure and economic loss associated with clinical disease in herds. This study sought to further characterize tick-borne pathogens present in Dermacentor ticks (n = 1,773) sampled in 2019 from 15 of Mongolia's 21 aimags (provinces). The ticks were morphologically identified and sorted into 377 pools which were then screened using Next-Generation Sequencing paired with confirmatory PCR and DNA sequence analysis. Rickettsia spp. were detected in 88.33% of pools, while Anaplasma spp. and Bartonella spp. were detected in 3.18 and 0.79% of pools, respectively. Khentii had the highest infection rate for Rickettsia spp. (76.61%; CI: 34.65-94.79%), while Arkhangai had the highest infection rate for Anaplasma spp. (7.79%; CI:4.04-13.72%). The exclusive detection of Anaplasma spp. in tick pools collected from livestock supports previous work in this area that suggests livestock play a significant role in disease maintenance. The detection of Anaplasma, Bartonella, and Rickettsia demonstrates a heightened risk for infection throughout Mongolia, with this study, to our knowledge, documenting the first detection of Bartonella melophagi in ticks collected in Mongolia. Further research deploying NGS methods is needed to characterize tick-borne pathogens in other endemic tick species found in Mongolia, including Hyalomma asiaticum and Ixodes persulcatus.

Hotspots in a cold land-reported cases of rabies in wildlife and livestock in Mongolia from 2012-2018.

The epidemiological profile of rabies virus within Mongolia remains poorly characterized despite 21,302 domestic animal cases being reported between 1970-2005. This lack of knowledge is particularly concerning given that roughly 26% of the population lives a pastoral herding lifestyle and livestock production contributes up to 18% of Mongolia's total gross domestic product (GDP). The gaps in knowledge of the rabies disease ecology within Mongolia combined with the lack of routine vaccination of domestic animals and wildlife poses a significant threat to the more than 60 million heads of livestock within Mongolia. Animal rabies case data from the General Authority for Veterinary Services and National Center for Zoonotic Diseases were used in this study. Each data point included year of report, an animal descriptor, geographic coordinates and the aimag (province) of origin. A total of 2,359 animal rabies cases were reported between 2012-2018. Cattle were the most commonly reported animal overall (861 cases), followed by goats (268), sheep (251) and dogs (221) within the domestic animal category. Red foxes were responsible for most reported wildlife cases (317) followed by wolves (151). Most rabid animals were reported in the Khuvsgul, Uvurkhangai and Govi-Altai aimags, and a positive correlation was found between livestock numbers per soum and the number of rabies cases reported. Rabies poses a significant threat to the Mongolian economy and the health of human and animal populations within Mongolia. The close association of the nomadic pastoralists with both domestic animals and wildlife represents a significant threat for disease emergence and necessitates studies that describe the ecology of rabies, which may threaten these populations.

Two fatal cases of plague after consumption of raw marmot organs.

Marmots are an important reservoir of Yersinia pestis and a source of human plague in Mongolia. We present two fatal cases of plague after consumption of raw marmot organs and discuss the distribution of natural foci of Y. pestis in Mongolia.

Geographic Range of Lyme Borreliosis in Mongolia.

Introduction: In Asia, Borrelia garinii, B. afzelii, and B. bavariensis are transmitted by Ixodes persulcatus ticks and clinically present with a wide range of neurological and arthritic symptoms. This report aims to provide details on the geographic distribution of suspected cases of Lyme borreliosis (LB), reported to local Mongolian hospitals between 2007 and 2017. Methods: This report examines 150 reported cases of suspected LB from 13 aimags (provinces) in Mongolia from April 2007 to August 2017, including date and location of infection, method of diagnosis (indirect immunofluorescent assay and/or enzyme-linked immunosorbent assay test), frequency of specific symptoms, and case demographics. Information was gathered through collaboration with the National Center of Communicable Disease and the National Center for Zoonotic Diseases. Results: Zavkhan and Selenge, located in northern Mongolia, had the highest percentage of reported suspected cases, with 25% and 20%, respectively. Ages ranged from 1 to 78 years, with a mean age of 26 years, however, 37% of individuals were younger than 10. More than twice as many women sought treatment as men, and the distribution of men who sought treatment was skewed toward children and the elderly. Most frequently reported symptoms include fever, rash, headache, and enlarged lymph glands. Furthermore, peak months of tick bite and treatment seeking occurred between April and June. Conclusions: Based on these preliminary findings, syndromic surveillance should be expanded across northern Mongolia, with LB considered in differential diagnosis for patients reporting a recent tick bite.

Low Prevalence of Enzootic Equine Influenza Virus among Horses in Mongolia.

Horses are critically important for Mongolian herders' livelihoods, providing transportation and food products, and playing important cultural roles. Equine influenza virus (EIV) epizootics have been frequent among Mongolia's horses, with five occurring since 1970. We sought to estimate the prevalence for EIV infection among horses and Bactrian camels with influenza-like illness between national epizootics. In 2016-2017, active surveillance for EIV was periodically performed in four aimags (provinces). Nasal swabs were collected from 680 horses and 131 camels. Seven of the horse swabs were "positive" for qRT-PCR evidence of influenza A (Ct value ≤ 38). Two more were "suspect positive" (Ct value > 38 and ≤ 40). These nine specimens were collected from four aimags. None of the camel specimens had molecular evidence of infection. Despite serial blind passage in Madin-Darby Canine Kidney cells (MDCK) cells, none of the nine horse specimens yielded an influenza A virus. None of the 131 herder households surveyed had recently vaccinated their horses against EIV. It seems likely that sporadic EIV is enzootic in multiple Mongolian aimags. This finding, the infrequent use of EIV vaccination, periodic prevalence of highly pathogenic avian influenza, and the mixing of domestic and wild equid herds suggest that Mongolia may be a hot spot for novel EIV emergence.

Detection of Babesia venatorum, Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis in Ixodes persulcatus ticks from Mongolia.

Information about the prevalence and geographical distribution of tick-borne pathogens Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, and Babesia spp. is still rare in Mongolia. We tested 275 Ixodes persulcatus ticks for A. phagocytophilum, Cand. N. mikurensis and Babesia spp. and 125 Dermacentor nuttalli ticks especially for Babesia spp. using different PCR methods. Ticks were collected from three provinces (Selenge, Arkhangai, Khentii) in Mongolia. DNA of A. phagocytophilum, Cand. N. mikurensis and Babesia spp. were found with a prevalence of 6.2%, 1.5% and 3.3% in each case in I. persulcatus ticks. This is the first time Cand. N. mikurensis was found in ticks from Mongolia. Sequence analysis of Babesia spp.-positive amplicons showed exclusively B. venatorum, which had also not been mentioned in Mongolia before. On the contrary, all D. nuttalli ticks tested negatively for Babesia spp. This study demonstrates that all three zoonotic pathogens are present in I. persulcatus ticks in Mongolia, and justify the need for further investigations of a more detailed genetic characterization of these pathogens.