First Molecular Evidence of Anaplasma phagocytophilum in Rodent Populations of Nanchang, China

Prevalence and zoonotic potential of pathogens in micromammals (rodents and insectivores) in the Republic of Korea

Micromammals (rodents and insectivores), are reservoirs of numerous zoonotic pathogens and play a critical role in infectious disease transmission. The rising prevalence of micromammals-associated pathogens in the Republic of Korea highlights the urgent need for targeted surveillance. Here, we analyzed micromammal blood samples collected from 16 nationwide sites during spring 2022, autumn 2022, and spring 2023 to investigate the following key zoonotic diseases: severe fever with thrombocytopenia syndrome, Lyme disease, Q fever, scrub typhus, anaplasmosis, ehrlichiosis, and rickettsioses. Our analysis revealed that of the 756 micromammal samples analyzed, 0.1 % had Borrelia afzelii, Borrelia valaisiana, and Orientia tsutsugamushi, 12.7 % contained Anaplasma phagocytophilum, and 82 % Neoehrlichia mikurensis. Importantly, we detected Borrelia valaisiana in micromammals in the Republic of Korea for the first time. Phylogenetic analysis identified close genetic links between local and global pathogen strains, highlighting potential cross-border transmission risks. The high prevalence of Neoehrlichia mikurensis emphasizes the zoonotic threat of micromammals. These findings provide crucial insights about enhancing micromammals-associate pathogen surveillance, inform public health strategies, and reinforce the importance of monitoring micromammal populations for zoonotic infection risk mitigation in Korea and beyond.

Molecular surveillance of zoonotic pathogens from wild rodents in the Republic of Korea

BACKGROUND

Rodents are recognized as major reservoirs of numerous zoonotic pathogens and are involved in the transmission and maintenance of infectious diseases. Furthermore, despite their importance, diseases transmitted by rodents have been neglected. To date, there have been limited epidemiological studies on rodents, and information regarding their involvement in infectious diseases in the Republic of Korea (ROK) is still scarce.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated rodent-borne pathogens using nested PCR/RT-PCR from 156 rodents including 151 Apodemus agrarius and 5 Rattus norvegicus from 27 regions in eight provinces across the ROK between March 2019 and November 2020. Spleen, kidney, and blood samples were used to detect Anaplasma phagocytophilum, Bartonella spp., Borrelia burgdorferi sensu lato group, Coxiella burnetii, Leptospira interrogans, and severe fever with thrombocytopenia syndrome virus (SFTSV). Of the 156 rodents, 73 (46.8%) were infected with Bartonella spp., 25 (16.0%) with C. burnetii, 24 (15.4%) with L. interrogans, 21 (13.5%) with A. phagocytophilum, 9 (5.8%) with SFTSV, and 5 (3.2%) with Borrelia afzelii. Co-infections with two and three pathogens were detected in 33 (21.1%) and 11 rodents (7.1%), respectively. A. phagocytophilum was detected in all regions, showing a widespread occurrence in the ROK. The infection rates of Bartonella spp. were 83.3% for B. grahamii and 16.7% for B. taylorii.

CONCLUSIONS/SIGNIFICANCE

To the best of our knowledge, this is the first report of C. burnetii and SFTSV infections in rodents in the ROK. This study also provides the first description of various rodent-borne pathogens through an extensive epidemiological survey in the ROK. These results suggest that rodents harbor various pathogens that pose a potential threat to public health in the ROK. Our findings provide useful information on the occurrence and distribution of zoonotic pathogens disseminated among rodents and emphasize the urgent need for rapid diagnosis, prevention, and control strategies for these zoonotic diseases.

Worldwide meta-analysis on Anaplasma phagocytophilum infections in animal reservoirs: Prevalence, distribution and reservoir diversity

A wide range of vertebrate species are competent reservoirs of Anaplasma phagocytophilum, where the pathogen is maintained in the enzootic cycle and transmitted to humans through activities of tick vectors. An insight into the role and diversity of these reservoirs is vital in understanding the epidemiology of this pathogen. Here, we determined the prevalence, distribution and reservoir diversity of A. phagocytophilum using a systematic review and meta-analysis. Data pooling was performed by the random-effects model, heterogeneity was assessed by the Cochran's Q-test and publication bias by Egger's regression test. Eighty-nine studies from 33 countries across 5 continents revealed A. phagocytophilum pooled prevalence of 15.18% (95% CI: 11.64, 19.57). Continental estimates varied significantly (p < 0.0001), with a range of 2.88% (95% CI: 0.25, 26.20) in South America to 19.91% (95% CI: 13.57, 28.24) in Europe. Country-based estimates ranged between 2.93% (95% CI: 1.17, 7.16) in Slovakia and 71.58% (95% CI: 25.91, 94.77) in Norway. Studies on A. phagocytophilum were concentrated in Europe (51.69%; 46/89) by continent and the USA (22.47%; 20/89) by country. Prevalence in wildlife (17.64%; 95% CI: 12.21-28.59) was significantly higher (p < 0.001) than that among domestic animals (10.68%; 95% CI: 6.61-16.83). Diverse species of wildlife, domestic animals and birds were infected by A. phagocytophilum. To curtail the public health, veterinary and economic consequences of A. phagocytophilum infections, we recommend an all-inclusive epidemiological approach that targets the human, animal and environmental components of the disease.

Zoonotic vector-borne bacteria in wild rodents and associated ectoparasites from Tunisia

Wild rodents are considered as potential carriers of several zoonotic vector-borne bacteria but their epidemiology is poorly understood in Tunisia. A total of 305 biological samples (100 spleens, 100 livers, 100 kidneys, and 5 pooled ectoparasites (Xenopsylla cheopis, Laelaps echidninus, Ornithonyssus sp., Hoplopleura sp. and eggs of the rat fleas)) were collected from 100 wild rodents from three Tunisian governorates. Molecular screening was performed to reveal infections with main vector-borne bacteria. Captured rodents belonged to three rodent genera and species including Rattus rattus (n = 51, 51%), Meriones shawi (n = 24, 24%) and Mus musculus (n = 25, 25%). Examined rodents were found to be heavily infested by the rat flea X. cheopis (n = 32, 47%) and the rat mite L. echidninus (n = 22, 32.3%). However, the rat mite Ornithonyssus sp. (n = 13, 19.1%) and the rat lice Hoplopleura sp. (n = 1, 1.5%) were rarely identified. Based on 16S rRNA and msp4 genes, infection with Anaplasmataceae bacteria was detected in six specimens of R. rattus and one M. shawi. Pathogenic A. phagocytophilum (n = 1), A. phagocytophilum-like 1 (Anaplasma sp. Japan) (n = 1), and A. ovis (n = 5) were identified. On the basis of ompB, ompA and gltA genes, infection with Rickettsia spp. was identified in three specimens of R. rattus and one of M. shawi. Five Rickettsia species of the spotted fever group, corresponding to R. monacensis, R. helvetica, R. massiliae, R. africae, and R. aeschlimannii, were detected in mixed infections. Bartonella henselae DNA was also found in two R. rattus, based on rpoB partial sequences. All revealed Anaplasma, Rickettsia and Bartonella bacteria were detected in spleen samples. Ehrlichia, Coxiella and Borrelia spp. were not identified in any of the tested samples. In Tunisia, this is the first report indicating infections with Anaplasma, Rickettsia and Bartonella spp. in wild rodents, particularly present alongside domestic livestock and human. This represents a serious risk of potential bacterial transmission. Thus, controlling rodent population in animal herds, residential areas and sensitizing local people to this risk seem absolutely necessary.

Preliminary investigation of ixodid ticks in Jiangxi Province of Eastern China

In recent years, a large effort has been made for tick surveys for public health importance around China, especially after outbreaks of severe fever with thrombocytopenia syndrome (SFTS) occurred in humans in 2009. In this paper, the preliminary species composition and population distribution of ticks in Jiangxi Province of Eastern China is reported. Ticks were collected in three habitats (grassland, shrubs and woodland) and from nine host groups in 12 sampling sites throughout Jiangxi Province between 2011 and 2018. Six tick species including Haemaphysalis longicornis, Rhipicephalus sanguineus sensu lato, Haemaphysalis yeni, Haemaphysalis kitaoka, Ixodes sinensis and Dermacentor auratus were collected from the vegetation. Haemaphysalis longicornis was most abundant tick species, accounting for 90.6% of the total ticks. Haemaphysalis yeni and H. kitaoka were newly recorded tick species in Jiangxi Province. Tick presence was remarkably greater in grassland (89.4%) than in woodland (9.4%) and shrubs (1.2%), and nymphs (68.2%) and larvae (19.1%) were more frequently found than adult females (6.6%) and males (6.0%). On hosts, a total of 1513 ticks, from 13 species and four genera, were collected. These were H. longicornis, Haemaphysalis campanulata, Haemaphysalis flava, Haemaphysalis phasiana, H. yeni, H. kitaoka, Haemaphysalis hystricis, R. sanguineus (s.l.), Rhipicephalus haemaphysaloides, Rhipicephalus microplus, Ixodes granulatus, I. sinensis and Amblyomma testudinarium. Amblyomma testudinarium was a newly recorded tick species in Jiangxi Province. Based on this investigation, H. longicornis was the most frequently collected species (30.5%) and widely distributed tick species of the total collection ticks (in 11 sampling sites). Haemaphysalislongicornis had a broad host range and its presence (hosts with at least one tick) was significantly greater on Lepus sinensis (33.3%) than on Canis familiaris (2.3%) (χ2 = 23.68, p = 0.0013). In addition, the number of H. longicornis collected on L. sinensis (64.0%) was higher than on other host groups. Of all ticks collected on hosts, different developmental stages were obtained, which included 347 larvae (22.9%), 249 nymphs (16.5%), 404 adult males (26.7%) and 513 females (33.9%) and sex distribution was relatively uniform. These data indicate that a broad range of tick species is widely distributed throughout Jiangxi Province in Eastern China.

Tick-Borne Pathogens in Ixodid Ticks from Poyang Lake Region, Southeastern China

Ticks are the vectors of various pathogens, threatening human health and animal production across the globe. Here, for the first time we detected Ricketssia spp., Borrelia spp. and protozoan in ticks from Poyang Lake region in Ji- angxi Province of eastern China. In 3 habitat categories and on 12 host species, 311 ticks from 11 species were collected. Haemaphysalis longicornis was the predominant species, accounting for 55.63%, followed by Rhipicephalus microplus, Haemaphysalis flava and Ixodes granulatus. Of the collected ticks, 7.07% were positive for tick-borne pathogens, and H. longicornis and H. flava were found to be co-infected with Ricketssia spp. and protozoan. H. flava was the most detected positive for tick-borne pathogens, whereas H. longicornis had the lowest infection rate, and the difference in infection rates between tick species was significant (χ2=61.24, P<0.001). Furthermore, adult ticks demonstrated remarkably greater infection rate than immature ticks (χ2=10.12, P=0.018), meanwhile ticks on Erinaceidae showed significantly higher positivity than ticks collected on other host species (χ2=108.44, P<0.001). Genetic fragment sequencing and analyses showed at least 4 pathogen species presence in ticks, namely Borrelia yangtzensis, Rickettsia slovaca or Rickettsia raoultii related genospecies, Babesia vogeli and Hepatozoon canis or Hepatozoon felis related genospecies. The finding indicates that the abundant ticks can carry diverse pathogens in Poyang Lake region, and pathogen infection is highly related to species, vertebrate hosts and life stages of ticks.