The prevalence of Coxiella burnetii infection in wild Korean water deer, Korea

Seroprevalence of Coxiella burnetii antibodies in wild deer populations in eastern Australia

Coxiella burnetii causes significant reproduction losses in livestock and the disease Q fever in humans. Transmission of C. burnetii is facilitated by the stability of the bacterium in the environment and the susceptibility of a variety of host species to infection. Consequently, inter-species transmission occurs frequently through either direct or indirect contact. Wildlife may represent reservoirs of C. burnetii and could therefore be a source of infection for domestic animals. Understanding the prevalence of C. burnetii infections at the wildlife-livestock interface is important for disease control. This study aimed to investigate the extent of C. burnetii exposure in wild deer in eastern Australia. Serum samples were obtained from 413 wild deer from seven regions in four eastern Australian states from 2017 to 2020. Antibodies were detected using a commercial Q fever antibody kit validated for ruminants. Seroprevalence of C. burnetii antibodies in deer was determined and true prevalence estimated, for each region. The overall seroprevalence of C. burnetii antibodies in wild deer was 3.4% (14 seropositive of 413 deer sampled) with true prevalence estimated to be 4.3% (95% credible interval: 0.6%, 10.9%). Seropositive deer were identified only in Queensland (7/108 seropositive) and northern New South Wales (7/120 seropositive). This geospatial distribution is consistent with seropositivity in other animal species and indicative of the level of C. burnetii in the environment. The low seroprevalence suggests that wild deer are unlikely to be a major reservoir species for C. burnetii in eastern Australia but may still be implicated in inter-species transmission cycles.

Identification of Zoonotic Tick-Borne Pathogens from Korean Water Deer (Hydropotes inermis argyropus)

Korean water deer (Hydropotes inermis argyropus) are widespread in the Republic of Korea (ROK). Mostly, Korean water deer are essential hosts for maintaining ticks and tick-borne diseases (TBDs). Here, we investigated the prevalence of tick-borne pathogens (TBPs) among rescued Korean water deer. Anaplasma phagocytophilum (21.4%, 6/28), Anaplasma capra (14.3%, 4/28), Babesia capreoli (3.6%, 1/28), and Coxiella burnetii (3.6%, 1/28) were detected, but Borrelia burgdorferi, Ehrlichia, Rickettsia, and Theileria infections were not found. A. phagocytophilum was the most commonly detected pathogen, and co-infection with A. capra and B. capreoli was also noted in one Korean water deer. To our knowledge, this is the first article of B. capreoli infection in Korean water deer in the ROK. The infecting isolate of A. phagocytophilum was genetically characterized by 16S ribosomal RNA (rRNA) gene and ankyrin-related protein (ankA) gene. Although the 16S rRNA gene alone may not be informative enough to delineate distinct host species, ankA-based phylogeny revealed a high identity of Korean water deer sequences with those of the causative agent of human granulocytic anaplasmosis. A. capra was detected by using citrate synthase gene (gltA), heat-shock protein (groEL), and major surface protein 4 (msp4) genes. Phylogenetic tree based on these gene markers revealed that there were at least two distinct variants within A. capra circulating in the ROK. One variant originated from different hosts including humans, ticks, goats, and sheep, whereas the other variant was reported recently in Korean water deer in the ROK. Consequently, these sequences were identified to belong to a zoonotic species. Sequencing analysis of the 18S rRNA gene revealed that our isolate belonged to B. capreoli and was distinct from Babesia divergens and Babesia venatorum. Moreover, our isolate showed 92.2% homology with B. capreoli sequences, indicating that these differences may be attributed to the different tick species that transmit B. capreoli or to different host species. Genotyping and phylogenetic analysis of C. burnetii based on 16S rRNA and IS1111 genes revealed that our isolate was grouped with several strains of C. burnetii and was genetically distant from Coxiella-like bacteria isolates. The present results highlight that Korean water deer act as potential reservoir hosts for zoonotic TBPs, and thus play an important role in the transmission of TBDs in humans, animals, and livestock.

Evidence of exposure to Coxiella burnetii in neotropical free-living cervids in South America

Coxiella burnetii (order Legionellales, family Coxiellaceae), the etiological agent of Q fever, is a pleomorphic, obligate Gram-negative intracellular bacillococcus that can infect humans and animals. Among the mammals hosting this agent, both domestic and wild ruminants are of particular economic and public health importance. Ticks and other hematophagous arthropods or aerosols are incriminated in the transmission between reservoirs and susceptible hosts. This study used serological and molecular methods to investigate the C. burnetii occurrence in blood samples from free-living deer (143 Blastocerus dichotomus, 27 Mazama gouazoubira, 4 M. bororo, 3 M. americana, and 11 Ozotocerus bezoarticus) sampled in Mato-Grosso do Sul, São Paulo, Goiás and Paraná states in Brazil. The DNA extracted from the blood samples of 188 cervids was submitted to nested (n) PCR for C. burnetii based on the IS1111 repetitive insertion element of the heat shock protein (htpAB) gene. Additionally, 169 serum samples were submitted to Indirect Immunofluorescence Assay (IFAT) to detect Ig antibodies to C. burnetii. The nPCR results indicated that all blood samples were negative, evidencing the absence of circulating C. burnetii DNA in cervids from the studied regions or, alternatively, the C. burnetii DNA concentration in the deer blood samples was below the threshold of the used PCR technique. On the other hand, 5.32% (9/169) of deer were seropositive for C. burnetii by IFAT, with titers ranging from 256 and 16,384. In conclusion, the present work showed the first evidence of exposure of free-living deer to C. burnetii in Brazil.

Coxiella burnetii (Q fever) Infection in Farmed Ruminants in Three Northeastern Provinces and Inner Mongolia Autonomous Region, China

Coxiella burnetii is the pathogenic agent of Q fever, a zoonosis that occurs worldwide. In China, the organism infects people and a wide range of wild and farmed animals. However, little is known about C. burnetii infection in farmed ruminants in northeastern China, and there appears to have been no previous study on sika deer. The present study was conducted to determine the seroprevalence of C. burnetii in farmed ruminants in this region of China. A total of 3147 domestic ruminants (784 sheep, 1016 cattle, and 1347 sika deer) were randomly collected for this study. An indirect enzyme-linked immunosorbent assay kit was used to detect the antibodies to C. burnetii. The results showed an overall seroprevalence of 16.7% in domestic ruminants (24.9%, 13.5%, and 12.3% in cattle, sheep, and sika deer, respectively). This is the first report of C. burnetii seroprevalence in sika deer in China. Protective and hygiene measures should be applied in farm management to reduce the risk of exposure of C. burnetii to humans.

RETROSPECTIVE ANALYSIS OF THE EPIDEMIOLOGIC LITERATURE, 1990-2015, ON WILDLIFE-ASSOCIATED DISEASES FROM THE REPUBLIC OF KOREA

To assess the status of research on wildlife diseases in the Republic of Korea (ROK) and to identify trends, knowledge gaps, and directions for future research, we reviewed epidemiologic publications on wildlife-associated diseases in the ROK. We identified a relatively small but rapidly increasing body of literature. The majority of publications were focused on public or livestock health and relatively few addressed wildlife health. Most studies that focused on human and livestock health were cross-sectional whereas wildlife health studies were mostly case reports. Fifteen diseases notifiable to the World Organisation for Animal Health were identified and 21 diseases were identified as notifiable to either the Korea Ministry of Health and Welfare or the Korea Ministry of Agriculture, Food and Rural Affairs. Two diseases were reported as occurring as epidemics; highly pathogenic avian influenza (HPAI) and virulent Newcastle disease. Six diseases or disease agents were described in the literature as emerging including HPAI, rabies, Babesia microti , avian coronaviruses, scrub typhus, and severe fever thrombocytopenia syndrome virus. The diseases for which there were the largest number of publications were HPAI and rabies. The majority of wildlife-associated zoonotic disease publications focused on food-borne parasitic infections or rodent-associated diseases. Several publications focused on the potential of wildlife as reservoirs of livestock diseases; in particular, Korean water deer ( Hydropotes inermis argyropus ) and wild boar ( Sus scrofa ). In contrast, there were few publications on diseases of concern for wildlife populations or research to understand the impacts of these diseases for wildlife management. Increased focus on prospective studies would enhance understanding of disease dynamics in wildlife populations. For the high-consequence diseases that impact multiple sectors, a One Health approach, with coordination among the public health, agricultural, and environmental sectors, would be important. This type of review can provide useful information for countries or regions planning or implementing national wildlife health programs.

PREVALENCE OF ANTIBODY TO AND DNA OF LAWSONIA INTRACELLULARIS IN SAMPLES FROM WILD ANIMALS IN KOREA

We evaluated the prevalence of Lawsonia intracellularis infection in three wild animal species in Korea; the Korean water deer ( Hydropotes inermis ), Siberian roe deer ( Capreolus pygargus ), and raccoon dogs ( Nyctereutes procyonoides ). We collected 136 sera and 109 fecal samples from individuals in 10 Wildlife Rescue and Conservation Centers. Serum samples were tested for anti- L. intracellularis antibodies using a blocking enzyme-linked immunosorbent assay (bELISA), and fecal samples were subjected to a real-time PCR assay for L. intracellularis . Thirty-five (25.7%) sera and 36 (33.0%) fecal samples were positive. We found a higher proportion of positive sera (64.7%, χ²=15.439, P<0.01) and feces (58.8%, χ²=6.126, P<0.05) in raccoon dogs (χ²=11.855, P<0.01) than in the other species (20% positive sera and 29% positive feces in Korean water deer; 20% positive sera and 25% positive feces in Siberian roe deer). Our data indicate infection by L. intracellularis in Korean water deer, Siberian roe deer, and raccoon dogs throughout the country. It is imperative to know whether these infected animal species are natural hosts for L. intracellularis in addition to domestic pigs ( Sus scrofa domesticus).

Detection and Genotyping of Coxiella burnetii and Coxiella-Like Bacteria in Horses in South Korea

Coxiella burnetii and Coxiella-like bacteria (CLB) are genetically and ecologically distinct despite some genetic similarities. Furthermore, CLB are exceptionally diverse and widespread in ticks, but rarely detected in domestic animals. Since Coxiella bacteria can be transmitted from infected horses by inhalation or by coming in contact with ticks during activities such as horseback riding, it is necessary to study their prevalence. To the best of our knowledge, this is the first large-scale nationwide investigation of the prevalence of C. burnetii and CLB among horses reared in South Korea. Of 816 blood samples collected between 2007 and 2013, 11 (1.3%) were identified as C. burnetii by ELISA, and six (0.7%) as CLB by 16S rRNA sequencing. While a sequence from Jeju Island was similar (97.9–100%) to those within clade B, five sequences obtained from the northern region were categorized into a new clade, indicating the sequence diversity of the genus Coxiella. Studies until date had detected CLB only in ticks; here, we describe their detection in mammals. Given their zoonotic potential, strategic monitoring and appropriate control programs for Coxiella species need to be established.

Coxiella burnetii Seroprevalence and Risk Factors in Cattle Farmers and Farm Residents in Three Northeastern Provinces and Inner Mongolia Autonomous Region, China

Little is known about Coxiella burnetii infection among cattle farmers and farm residents in China. Thus, the present study was conducted to detect the seroprevalence of C. burnetii infection and estimate associated risk factors among cattle farmers and farm residents in China. A cross-sectional study was designed, and sera of 362 people living or working on 106 cattle farms were tested for C. burnetii IgG and IgM antibodies by immunofluorescence assay. Overall C. burnetii seroprevalence was 35.6% (129/362, 95% CI: 30.70–40.57), and 112 participants had experienced a past infection and seventeen (4.7%) had experienced a relatively recent infection. In the final combined multilevel model, the following activities were significantly associated with presence of antibodies against C. burnetii: milking cattle, providing general healthcare to cattle, providing birth assistance, contact dead-born animals, urbanization, and presence of mice and/or rats in the stable. Moreover, presence of disinfection equipment was a significant protective factor. This is the first study addressing the seroprevalence and risk factors of C. burnetii infection in cattle farmers and farm residents in three northeastern provinces and Inner Mongolia Autonomous Region, China.

Detection of Tick-Borne Pathogens in the Korean Water Deer (Hydropotes inermis argyropus) from Jeonbuk Province, Korea

The objective of this study was to investigate the prevalence of tick-borne pathogens in the Korean water deer (Hydropotes inermis argyropus). Pathogens were identified using PCR which included Anaplasma, Ehrlichia, Rickettsia, and Theileria. Rickettsia was not detected, whereas Anaplasma, Ehrlichia, and Theileria infections were detected in 4, 2, and 8 animals, respectively. The most prevalent pathogen was Theileria. Of the 8 Theileria-positive animals, 2 were mixed-infected with 3 pathogens (Anaplasma, Ehrlichia, and Theileria) and another 2 animals showed mixed-infection with 2 pathogens (Anaplasma and Theileria). Sequencing analysis was used to verify the PCR results. The pathogens found in this study were identified as Anaplasma phagocytophilum, Ehrlichia canis, and Theileria sp. To the best of our knowledge, this is the first report identifying these 3 pathogens in the Korean water deer. Our results suggest that the Korean water deer may serve as a major reservoir for these tick-borne pathogens, leading to spread of tick-borne diseases to domestic animals, livestock, and humans. Further studies are needed to investigate their roles in this respect.