Effect of environmental variables on the abundance of Amblyomma ticks, potential vectors of Rickettsia parkeri in central Brazil

Amblyomma ticks are vectors of both Rickettsia rickettsii and R. parkeri in the Americas, where capybaras (Hydrochoerus hydrochaeris) are the main hosts in urban areas, thus contributing to the transmission of spotted fever. Herein, we studied: (i) the seasonal dynamics and abundance of ticks in areas where capybaras live, (ii) the effect of environmental variables on tick abundance, and (iii) the presence of Rickettsia-infected ticks. Between September 2021 and September 2022, we sampled ticks using cloth-dragging at 194 sites on the shore of Lake Paranoá in Brasília, Brazil. We measured environmental data (season, vegetation type, canopy density, temperature, humidity, and presence or vestige of capybara) at each site. Nymphs and adults were morphologically identified to the species level, and a selected tick sample including larvae was subjected to genotypic identification. We investigated Rickettsia-infected ticks by PCR (gltA, htrA, ompB, and ompA genes) and associations between tick abundance and environmental variables using Generalized Linear Models. A total of 30,334 ticks (96% larvae) were captured. Ticks were identified as Amblyomma, with A. sculptum comprising 97% of the adult/nymphs. Genotype identification of a larval sample confirmed that 95% belonged to A. dubitatum. Seasonal variables showed significant effects on tick abundance. Most larvae and nymphs were captured during the early dry season, while the adults were more abundant during the wet season. Vegetation variables and the presence of capybaras showed no association with tick abundance. Rickettsia parkeri group and R. bellii were identified in A. dubitatum, while A. sculptum presented R. bellii. We conclude that: (i) Amblyomma ticks are widely distributed in Lake Paranoá throughout the year, especially larvae at the dry season, (ii) the abundance of Amblyomma ticks is explained more by climatic factors than by vegetation or presence of capybaras, and (iii) A. dubitatum ticks are potential vectors of R. parkeri in Brasília.

Density and behavior of capybara (Hydrochoerus hydrochaeris) ticks (Acari: Ixodidae) Amblyomma sculptum and Amblyomma dubitatum with notes on Rickettsia bellii infection: Assessing human exposure risk

In several urban and peri‑urban areas of Brazil, populations of Amblyomma sculptum and Amblyomma dubitatum ticks are maintained by capybaras (Hydrochoerus hydrochaeris). In some of these areas, this host and these tick species are associated with Brazilian spotted fever (BSF), a lethal human disease caused by the bacterium Rickettsia rickettsii. In this work, we evaluated the risk of human exposure to these tick species using four collection techniques to discern host-seeking behavior. The study was carried out in 10 urban sites inhabited by capybaras in Uberlândia, a BSF-free municipality in southeastern Brazil. Ticks were collected in areas of 400 m2 at each site and at three seasons. Within the same municipality, the distance and speed of A. sculptum nymphs moving towards the CO2 traps were evaluated. In a sample of ticks Rickettsia DNA was investigated. During the study period, 52,953 ticks were collected. Among these, 83.4 % were A. sculptum (1,523 adults, 10,545 nymphs and 32,104 larvae) and 16.6 % were A. dubitatum (464 adults, 2,153 nymphs and 6,164 larvae). An average annual questing tick density of 4.4/m² was observed, with the highest density recorded at one site in autumn (31.8/m²) and the lowest in summer at another site (0.03/m²). The visual search yielded the highest proportion of A. sculptum larvae, constituting 47 % of the total and 63.6 % of all A. sculptum larvae. In contrast, CO2 traps collected a greater proportion of nymphs and adults of A. sculptum ticks. In the case of A. dubitatum, the CO2 trap was the most efficient technique with 57.7 % of captures of this species, especially of nymphs (94.5 % of captures) and adults (97.8 % of captures). Ticks' ambush height on vegetation (9 to 77 cm), observed by visual search 30 times, yielded a total of 20,771 ticks. Of these, 28 (93 %) were A. sculptum ticks, with only two (7 %) identified as A. dubitatum ticks. Among A. sculptum ticks, the nymph was the most attracted stage to humans and larva in the case of A. dubitatum. Amblyomma sculptum adults and nymphs were significantly more attracted to humans than those of A. dubitatum, but A. dubitatum larvae were significantly more attracted than the same stage of A. sculptum. The maximum distance and speed of horizontal displacement for A. sculptum nymphs were five meters and 2.0 m/h, respectively. The only species of Rickettsia detected in ticks, exclusively in A. dubitatum, was R. bellii. Importantly, it was observed that the higher the proportion of A. sculptum in the community of ticks, the lower the rate of infection of A. dubitatum by R. bellii. In conclusion, host-seeking behavior differed between the two tick species, as well as between stages of the same species. A greater restriction of A. dubitatum ticks to the soil was observed, while larvae and nymphs of A. sculptum dispersed higher in the vegetation. The behavior presented by A. sculptum provides greater opportunities for contact with the hosts, while A. dubitatum depends more on an active search for a host, the hunter behavior. Taken together, these observations show that a human being crossing an area infested with A. sculptum and A. dubitatum ticks will have almost exclusive contact with A. sculptum larvae and/or nymphs. Humans in a stationary position (sitting, lying or immobile) are exposed to both tick species, but they are more attractive to adults and mainly nymphs of A. sculptum compared to the corresponding stages of the tick A. dubitatum. The negative effect of A. sculptum on A. dubitatum infection by R. bellii deserves further studies.

An impedimetric immunosensor for diagnosis of Brazilian spotted fever in blood plasma

Brazilian spotted fever (BSF) is a serious disease of medical importance due to its rapid evolution and high lethality. The effectiveness of the treatment mainly depends on the rapid diagnosis, which is currently performed by indirect immunofluorescence and PCR tests, which require high costs and laboratory structure. In order to propose an alternative methodology, we sought to develop an impedimetric immunosensor (IM) based on the immobilization of specific IgY antibodies for IgG anti Rickettsia rickettsii, using blood plasma from capybara (Hydrochoerus hydrochaeris), for characterization, validation and applications of the ready IM. IM selectivity was observed when comparing capybara reagent IgG (IgGcr) readings with non-reagent IgG (IgGnr). A reagent IgG calibration curve was obtained, from which the limits of detection (LOD) and quantification (LOQ) of 1.3 ng mL-1 and 4.4 ng mL-1 were calculated, respectively. The accuracy tests showed that different concentrations of IgGcr showed a maximum deviation of 20.0%, with CI between 90.00% and 95.00%. Intermediate precision tests showed a relative standard deviation of 2.09% for researcher 1 and 2.61% for researcher 2, and the F test showed no significant difference between the recovery values found between the two analysts, since Fcal 1.56 < 5.05 and P-value 0.48 > 0, 05. Therefore, an impedimetric immunosensor was developed to detect anti BSF IgG in capybara blood plasma, which greatly contributes to the improvement of diagnostic tests, cost reduction and ease of execution.

Cattle Farming and Plantation Forest are Associated with Bartonella Occurrence in Wild Rodents

Bartonella spp. are intracellular hemotropic bacteria primarily transmitted by arthropod vectors to various mammalian hosts, including humans. In this study, we conducted a survey on wild populations of sigmodontine rodents, Akodon azarae and Oxymycterus rufus, inhabiting the Paraná River delta region. The study involved eight grids organized in a crossed 2 × 2 design, where four of the grids were exposed to cattle while the other four were not, and four grids were located in implanted forest while the remaining four were in natural grasslands. Our objective was to examine whether the occurrence of Bartonella spp. in rodents was associated with silvopastoral activities (cattle raising associated with timber production) conducted in the region. Additionally, we evaluated the associations between Bartonella infection and other environmental and host factors. We present compelling evidence of a significant positive association between Bartonella prevalence and the presence of implanted forests and cattle. Furthermore, we identified the presence of a Bartonella genotype related to the pathogen Bartonella rochalimaea, infecting both A. azarae and Ox. rufus. These findings suggest that anthropogenic land-use changes, particularly the development of silvopastoral practices in the region, may disrupt the dynamics of Bartonella.

Bartonella in Norway rats (Rattus norvegicus) from the urban slum environment in Brazil

Bartonella are rodent-borne bacteria that cause varied human etiologies. Studies on synanthropic rodents are rare, causing gaps in epidemiological knowledge. We tested bloodclot samples from 79 rats from an urban slum in Salvador, Brazil through PCR targeting gltA gene. Nine samples (11.4%) were positive: six had 100% identity with Bartonella sp. isolate JF429580 and 99.5% with B. queenslandensis strain AUST/NH8; three were 100% identical to isolate JF429532 and 99.7% to B. tribocorum. This is the second report on urban rat Bartonella indicating bacterial circulation at detectable rates. Its presence in rats from vulnerable human settlements demands public health attention.

Zoonotic pathogens identified in rodents and shrews from four provinces, China, 2015-2022

Rodents and shrews are major reservoirs of various pathogens that are related to zoonotic infectious diseases. The purpose of this study was to investigate co-infections of zoonotic pathogens in rodents and shrews trapped in four provinces of China. We sampled different rodent and shrew communities within and around human settlements in four provinces of China and characterised several important zoonotic viral, bacterial, and parasitic pathogens by PCR methods and phylogenetic analysis. A total of 864 rodents and shrews belonging to 24 and 13 species from RODENTIA and EULIPOTYPHLA orders were captured, respectively. For viral pathogens, two species of hantavirus (Hantaan orthohantavirus and Caobang orthohantavirus) were identified in 3.47% of rodents and shrews. The overall prevalence of Bartonella spp., Anaplasmataceae, Babesia spp., Leptospira spp., Spotted fever group Rickettsiae, Borrelia spp., and Coxiella burnetii were 31.25%, 8.91%, 4.17%, 3.94%, 3.59%, 3.47%, and 0.58%, respectively. Furthermore, the highest co-infection status of three pathogens was observed among Bartonella spp., Leptospira spp., and Anaplasmataceae with a co-infection rate of 0.46%. Our results suggested that species distribution and co-infections of zoonotic pathogens were prevalent in rodents and shrews, highlighting the necessity of active surveillance for zoonotic pathogens in wild mammals in wider regions.

Geographical distribution of scrub typhus and risk of Orientia tsutsugamushi infection in Indonesia: Evidence mapping

BACKGROUND

Scrub typhus is a potentially fatal acute febrile illness caused by bacteria in the genus Orientia. Though cases have been documented, a comprehensive body of evidence has not previously been compiled to give an overview of scrub typhus in Indonesia. This study aimed to address this key knowledge gap by mapping and ranking geographic areas based on existing data on the presence or absence of the pathogen in humans, vectors, and host animals.

METHODOLOGY/PRINCIPAL FINDINGS

We performed searches on local and international electronic databases, websites, libraries, and collections including Embase, Medline, and Scopus to gather relevant evidence (including grey literature). After extracting data on the presence and absence of the pathogen and its vectors, we ranked the evidence based on the certainty for the presence of human infection risk. The country was divided into subnational units, and each were assigned a score based on the evidence available for that unit. We presented this in an evidence map. Orientia tsutsugamushi presence has been identified on all the main islands (Sumatra, Java, Borneo, Celebes, Papua). About two thirds of the data points were collected before 1946. South Sumatra and Biak had the strongest evidence for sustaining infectious vectors. There was only one laboratory confirmed case in a human identified but 2,780 probable cases were documented. The most common vector was Leptotrombidium deliense.

CONCLUSIONS/SIGNIFICANCE

Our review highlights the concerning lack of data on scrub typhus in Indonesia, the fourth most populous country in the world. The presence of seropositive samples, infected vectors and rodents confirm O. tsutsugamushi is widespread in Indonesia and likely to be causing significant morbidity and mortality. There is an urgent need to increase surveillance to better understand the burden of the disease across the archipelago and to inform national empirical fever treatment guidelines.

Leptospira spp. in Free-Ranging Capybaras (Hydrochoerus hydrochaeris) from Midwestern Brazil

Background: Leptospirosis is a contagious disease that affects domestic and wild animals as well as humans. It is caused by infection with some pathogenic species of the genus Leptospira. In Brazil, studies on leptospirosis in capybaras are scarce or nonexistent in some regions, such as the Federal District. The objective of this study was to analyze the presence of DNA of the agent and/or anti-Leptospira spp. antibodies in capybaras. Materials and Methods: Blood samples were collected from 56 free-living capybaras captured in two different sites in the study region. The samples were submitted to hematology and clinical chemistry tests. To identify Leptospira positive samples, a conventional PCR (cPCR) and analysis of anti-Leptospira spp. antibodies by microscopic agglutination test (MAT) were used. Results: No animal showed cPCR amplification of the Lip32 gene, but 41.1% (23/56) of the animals had anti-Leptospira spp. antibodies on MAT. The serovars present were icterohaemorrhagiae (82.61%), copenhageni (65.22%), grippotyphosa (4.35%), and hardjo (4.35%). In the laboratorial tests, differences (p < 0.05) were observed in the biochemical assays of alkaline phosphatase, creatinine, albumin, and globulin. Although these values differed significantly between groups, they all remained within reference range (excluding albumin), and thus there is not enough to infer that this alteration could be caused by Leptospira infection. Conclusions: cPCR using whole blood samples to evaluate Leptospira spp. infection of free-living capybaras was not an efficient tool. The presence of Leptospira seroreactive capybaras shows that the bacteria are circulating in the urban environment of the Federal District.

Lack of molecular evidence of fecal-borne viruses in capybaras from São Paulo state, Brazil, 2018-2020: a minor public health issue

Capybara (Hydrochoerus hydrochaeris) is the world's largest rodent species distributed throughout South America. These animals are incredibly tolerant to anthropogenic environments and are occupying large urban centers. Capybaras are known to carry potentially zoonotic agents, including R. rickettsia, Leishmania spp., Leptospira spp., Trypanosoma spp., Salmonella spp., Toxoplasma gondii, and rabies virus. Focusing on the importance of monitoring potential sources of emerging zoonotic viruses and new viral reservoirs, the aim of the present study was to assess the presence of fecal-borne viruses in the feces of capybaras living in urban parks in São Paulo state, Brazil. A total of 337 fecal samples were collected between 2018 and 2020 and screened for the following: (i) Rotavirus group A (RVA) by ELISA; (ii) non-RVA species and Picobirnavirus (PBV) using PAGE; (iii) Human Bocaparvovirus (HBoV), Bufavirus (BuV), Tusavirus (TuV), and Cutavirus (CuV) qPCR; (iv) Human Enterovirus (EV), Norovirus GII (NoV), and Hantavirus by in houses RT-qPCR; (v) SARS-CoV-2 via commercial RT-qPCR kit assay; and (vi) Astrovirus (AstV) and Adenovirus (AdV) using conventional nested (RT)-PCRs. All fecal samples tested were negative for fecal-borne viruses. This study adds further evidence that the fecal-borne viruses is a minor public health issue in Brazilian capybaras, at least during the surveillance period and surveyed areas. Continuous monitoring of sylvatic animals is essential to prevent and control the emergence or re-emergence of newly discovered virus as well as viruses with known zoonotic potential.

Host specificity and genetic diversity of Bartonella in rodents and shrews from Eastern China

Bartonella are vector-borne gram-negative facultative intracellular bacteria causing emerging infectious diseases worldwide, and two thirds of known Bartonella species are carried by rodents. We captured rodents, shrews and rodent ectoparasitic mites in rural areas of Qingdao City, Shandong Province, China from 2012 to 2021 and used the animal spleen tissues for the PCR amplification of Bartonella gltA and rpoB genes. PCR showed 9.4% (40/425) rodents, and 5.1% (12/235) shrews were positive for Bartonella. Seven Bartonella species including three novel species were identified in five rodent species and one shrew species, indicating the abundance and genetic diversity of Bartonella in rodents and shrews. The infection rate of each Bartonella species in the animal species was as below: novel Candidatus Bartonella crocidura in shrews Crocidura lasiura (5.1%, 12/235); novel Candidatus Bartonella cricetuli in hamsters Tscherskia triton (20%, 9/45); novel Candidatus Bartonella muris in striped field mice Apodemus agrarius (4.2%, 7/168) and house mice Mus musculus (1.5%, 2/135); Bartonella fuyuanensis in striped field mice (8.9%, 15/168) and house mice (0.7%, 1/135); Bartonella rattimassiliensis and Bartonella tribocorum in brown rats Rattus norvegicus (6.7%, 3/45 and 4.2%, 2/45, respectively); Bartonella queenslandensis in Chinese white-bellied rat Niviventer confucianus (12.5%, 1/8). These results suggest that Bartonella infected a variety of rodent and shrew species with high infection rate, but each Bartonella specie is restricted to infect only one or a few genetically closely related rodent species. In addition, Candidatus Bartonella cricetuli, Candidatus Bartonella muris and Bartonella coopersplainsensis were found in chigger Walchia micropelta (33.3%, 3/9), and B. fuyuanensis were found in chigger Leptotrombidium intermedium (4.1%, 1/24), indicating chiggers may be reservoirs of Bartonella. In conclusion, abundant genetic diversified Bartonella species are found to infect rodents, shrews and chiggers, but each Bartonella species has a strict rodent animal host specificity; and chigger mites may play a role in Bartonella transmission.

Diversity of Leptospira spp. in bats and rodents from Papua New Guinea

Leptospirosis is the most common bacterial zoonosis globally. The pathogen, Leptospira spp., is primarily associated with rodent reservoirs. However, a wide range of other species has been implicated as reservoirs or dead-end hosts. We conducted a survey for Leptospira spp. in bats and rodents from Papua New Guinea. Kidney samples were collected from 97 pteropodid bats (five species), 37 insectivorous bats from four different families (six species) and 188 rodents (two species). Leptospires were detected in a high proportion of pteropodid bats, including Nyctimene cf. albiventer (35%), Macroglossus minimus (34%) and Rousettus amplexicaudatus (36%). Partial sequencing of the secY gene from rodent and bat leptospires showed host species clustering, with Leptospira interrogans and L. weilii detected in rodents and L. kirschneri and a potential novel species of Leptospira detected in bats. Further research is needed in Papua New Guinea and other locales in the Pacific region to gain a better understanding of the circulation dynamics of leptospires in reservoir species and the risks to public and veterinary health.

Ecology and distribution of Leptospira spp., reservoir hosts and environmental interaction in Sri Lanka, with identification of a new strain

Leptospirosis is a neglected zoonotic disease and one of the leading causes of zoonotic morbidity and mortality, particularly in resource-poor settings. Sri Lanka has one of the highest disease burdens worldwide, with occasional endemic leptospirosis outbreaks (2008, 2011). Rodents are considered the main wildlife reservoir, but due to a scarcity of studies it is unclear which particular species contributes to bacterial transmission and reservoir maintenance in this multi-host multi-parasite system. Several rodent species act as agricultural pests both in rice fields and in food storage facilities. To unravel the interactions among the small mammal communities, pathogenic Leptospira spp. and human transmission pathways, we collected animals from smallholder food storage facilities, where contact between humans and small mammals is most likely, and screened kidney tissue samples for Leptospira spp. using PCR. Samples were collected in three climatic zones along a rainfall gradient. Pathogenic Leptospira spp. were detected in small mammal communities in 37 (74%) out of 50 sampled farms and 61 (12%) out of 500 collected individuals were infected. The small mammal community was comprised of Rattus rattus (87.6%), Suncus shrews (8.8%), Bandicota spp. (2.8%) and Mus booduga (0.8%). Three pathogenic Leptospira spp. were identified, L. borgpetersenii (n = 34), L. interrogans (n = 15), and L. kirschneri (n = 1). Suncus shrews were commonly infected (32%), followed by B. indica (23%) and R. rattus (10%). L. borgpetersenii strains similar to strains previously extracted from human clinal samples in Sri Lanka were detected in R. rattus and Suncus shrews. L. interrogans was observed in R. rattus only. A single L. kirschneri infection was found in M. booduga. The presence of human pathogenic Leptospira species in an agricultural pest rodent (R. rattus) and in commensal shrews (Suncus) calls for management of these species in commensal settings. Further investigation of the interplay between pathogen and reservoir population dynamics, overlap in geographic range and the extent of spill-over to humans in and around rural settlements is required to identify optimal management approaches.

Fine-scale prevalence and genetic diversity of urban small mammal-borne pathogenic Leptospira in Africa: A spatiotemporal survey within Cotonou, Benin

Leptospirosis is a zoonotic disease that is caused by spirochete bacteria of the genus Leptospira. Around the world, one million people each year are infected, leading to 60,000 deaths. Infection occurs through contact with environmental pathogens excreted by mammals (notably rodents). Data on Leptospira and leptospirosis in Africa are rather scarce, especially in urban habitats though these appear to be favourable environments for the pathogen circulation and human contamination. Using qPCR, DNA sequencing as well as MST/VNTR approaches, we examined Leptospira occurrence and genetic diversity in 779 commensal small mammals that were sampled over 2 years in the city centre of Cotonou, Benin, from three neighbourhoods with contrasting socio-environmental conditions. Overall prevalence reached 9.1%. However, very marked variations in both space and time were observed, with local peaks of high prevalence but no clear seasonal pattern. In most sites that could be regularly sampled, Leptospira-positive rodents were found at least once, thus confirming the widespread circulation of the pathogen within small mammal communities of Cotonou. Interestingly, an unusual diversity of small mammal-borne Leptospira species and genotypes was retrieved, with up to four species and three different genovars within the same neighbourhood, and even instances of two species and two genovars identified simultaneously within the same household. To our knowledge, such a high genetic diversity has never been described at such a fine scale, a fortiori in Africa and, more generally, within an urban environment. Altogether, our results underline that much remains unknown about leptospirosis as well as the associated infectious risk in African cities where the disease may be massively over-looked.

Presence of Leptospira spp. and absence of Bartonella spp. in urban rodents of Buenos Aires province, Argentina

Big cities of Argentina are characterized by a strong social and economic fragmentation. This context enables the presence of urban rodents in close contact to the human population, mostly in the peripheral areas of the cities. Urban rodents can harbor a large variety of zoonotic pathogens. The aim of this study was to molecularly characterize Leptospira spp. and Bartonella spp. in urban rodents from the area of Gran La Plata, Buenos Aires province, Argentina. The species of urban rodents captured and tested were Rattus norvegicus, Rattus rattus, and Mus musculus. Leptospira interrogans and L. borgpetersenii were detected in R. norvegicus and M. musculus respectively. Bartonella spp. DNA was not detected in any of the kidney samples tested. No significant differences were observed between the prevalence of bacteria and rodent and environmental variables such as host sex, presence of stream and season by Generalized Linear Model analysis. These results confirm the role of urban rodents as infection sources of Leptospira spp., suggesting the need to implement public health measures to prevent the transmission of Leptospira spp. and other zoonotic pathogens from rodents to humans. Bartonella was not detected in this set of samples.

Genetic source tracking of human plague cases in Inner Mongolia-Beijing, 2019

On 12 November 2019, one couple from the Sonid Left Qi (County) in the Inner Mongolia Autonomous Region was diagnosed with pneumonic plague in Beijing. The wife acquired the infection from her husband. Thereafter, two bubonic plague cases were identified in Inner Mongolia on November 16th and 24th. In this study, genome-wide single nucleotide polymorphism (SNP) analysis was used to identify the phylogenetic relationship of Yersinia pestis strains isolated in Inner Mongolia. Strains isolated from reservoirs in 2018 and 2019 in Inner Mongolia, together with the strain isolated from Patient C, were further clustered into 2.MED3m, and two novel lineages (2.MED3q, 2.MED3r) in the 2.MED3 population. According to the analysis of PCR-based molecular subtyping methods, such as the MLVA 14 scheme and seven SNP allele sequencing, Patients A/B and D were classified as 2.MED3m. In addition, strains from rodents living near the patients' residences were clustered into the same lineage as patients. Such observations indicated that human plague cases originated from local reservoirs. Corresponding phylogenetic analysis also indicated that rodent plague strains in different areas in Inner Mongolia belong to different epizootics rather than being caused by spreading from the same epizootic in Meriones unguiculatus in 2019.

The microbiome and rodent models of immune mediated diseases

Over the last six decades production of laboratory rodents have been refined with the aim of eliminating all pathogens, which could influence research results. This has, however, also created rodents with little diversity in their microbiota. Until 10 years ago the impact of the microbiota on the outcome of rodent studies was ignored, but today it is clear that the phenotype of rodent models differs essentially in relation to the environment of origin, i.e. different breeders or different rooms. In this review, we outline the mechanisms behind gut bacterial impact on rodent models of immune mediated diseases, and how differences in environment of origin leads to phenotypic model differences within research areas such as infectious diseases and vaccine development, the metabolic syndrome, gut immunity and inflammation, autoimmunity and allergy. Finally, we sum up some tools to handle this impact to increase reproducibility and translatability of rodent models.

First investigation of pathogenic bacteria, protozoa and viruses in rodents and shrews in context of forest-savannah-urban areas interface in the city of Franceville (Gabon)

Rodents are reservoirs of numerous zoonotic diseases caused by bacteria, protozoans, or viruses. In Gabon, the circulation and maintenance of rodent-borne zoonotic infectious agents are poorly studied and are often limited to one type of pathogen. Among the three existing studies on this topic, two are focused on a zoonotic virus, and the third is focused on rodent Plasmodium. In this study, we searched for a wide range of bacteria, protozoa and viruses in different organs of rodents from the town of Franceville in Gabon. Samples from one hundred and ninety-eight (198) small mammals captured, including two invasive rodent species, five native rodent species and 19 shrews belonging to the Soricidae family, were screened. The investigated pathogens were bacteria from the Rickettsiaceae and Anaplasmataceae families, Mycoplasma spp., Bartonella spp., Borrelia spp., Orientia spp., Occidentia spp., Leptospira spp., Streptobacillus moniliformis, Coxiella burnetii, and Yersinia pestis; parasites from class Kinetoplastida spp. (Leishmania spp., Trypanosoma spp.), Piroplasmidae spp., and Toxoplasma gondii; and viruses from Paramyxoviridae, Hantaviridae, Flaviviridae and Mammarenavirus spp. We identified the following pathogenic bacteria: Anaplasma spp. (8.1%; 16/198), Bartonella spp. (6.6%; 13/198), Coxiella spp. (5.1%; 10/198) and Leptospira spp. (3.5%; 7/198); and protozoans: Piroplasma sp. (1%; 2/198), Toxoplasma gondii (0.5%; 1/198), and Trypanosoma sp. (7%; 14/198). None of the targeted viral genes were detected. These pathogens were found in Gabonese rodents, mainly Lophuromys sp., Lemniscomys striatus and Praomys sp. We also identified new genotypes: Candidatus Bartonella gabonensis and Uncultured Anaplasma spp. This study shows that rodents in Gabon harbor some human pathogenic bacteria and protozoans. It is necessary to determine whether the identified microorganisms are capable of undergoing zoonotic transmission from rodents to humans and if they may be responsible for human cases of febrile disease of unknown etiology in Gabon.

Limosilactobacillus balticus sp. nov., Limosilactobacillus agrestis sp. nov., Limosilactobacillus albertensis sp. nov., Limosilactobacillus rudii sp. nov. and Limosilactobacillus fastidiosus sp. nov., five novel Limosilactobacillus species isolated from the vertebrate gastrointestinal tract, and proposal of six subspecies of Limosilactobacillus reuteri adapted to the gastrointestinal tract of specific vertebrate hosts

Ten strains, BG-AF3-AT, pH52_RY, WF-MT5-AT, BG-MG3-A, Lr3000T, RRLNB_1_1, STM3_1T, STM2_1, WF-MO7-1T and WF-MA3-C, were isolated from intestinal or faecal samples of rodents, pheasant and primate. 16S rRNA gene analysis identified them as Limosilactobacillus reuteri. However, average nucleotide identity and digital DNA-DNA hybridization values based on whole genomes were below 95 and 70 %, respectively, and thus below the threshold levels for bacterial species delineation. Based on genomic, chemotaxonomic and morphological analyses, we propose five novel species with the names Limosilactobacillus balticus sp. nov. (type strain BG-AF3-AT=DSM 110574T=LMG 31633T), Limosilactobacillus agrestis sp. nov. (type strain WF-MT5-AT=DSM 110569T=LMG 31629T), Limosilactobacillus albertensis sp. nov. (type strain Lr3000T=DSM 110573T=LMG 31632T), Limosilactobacillus rudii sp. nov. (type strain STM3_1T=DSM 110572T=LMG 31631T) and Limosilactobacillus fastidiosus sp. nov. (type strain WF-MO7-1T=DSM 110576T=LMG 31630T). Core genome phylogeny and experimental evidence of host adaptation of strains of L. reuteri further provide a strong rationale to consider a number of distinct lineages within this species as subspecies. Here we propose six subspecies of L. reuteri: L. reuteri subsp. kinnaridis subsp. nov. (type strain AP3T=DSM 110703T=LMG 31724T), L. reuteri subsp. porcinus subsp. nov. (type strain 3c6T=DSM 110571T=LMG 31635T), L. reuteri subsp. murium subsp. nov. (type strain lpuph1T=DSM 110570T=LMG 31634T), L. reuteri subsp. reuteri subsp. nov. (type strain F 275T=DSM 20016T=ATCC 23272T), L. reuteri subsp. suis subsp. nov. (type strain 1063T=ATCC 53608T=LMG 31752T) and L. reuteri subsp. rodentium subsp. nov. (type strain 100-23T=DSM 17509T=CIP 109821T).

Investigating causality with fecal microbiota transplantation in rodents: applications, recommendations and pitfalls

In recent years, studies investigating the role of the gut microbiota in health and diseases have increased enormously - making it essential to deepen and question the research methodology employed. Fecal microbiota transplantation (FMT) in rodent studies (either from human or animal donors) allows us to better understand the causal role of the intestinal microbiota across multiple fields. However, this technique lacks standardization and requires careful experimental design in order to obtain optimal results. By comparing several studies in which rodents are the final recipients of FMT, we summarize the common practices employed. In this review, we document the limitations of this method and highlight different parameters to be considered while designing FMT Studies. Standardizing this method is challenging, as it differs according to the research topic, but avoiding common pitfalls is feasible. Several methodological questions remain unanswered to this day and we offer a discussion on issues to be explored in future studies.

Yersinia pestis: the Natural History of Plague

The Gram-negative bacterium Yersinia pestis is responsible for deadly plague, a zoonotic disease established in stable foci in the Americas, Africa, and Eurasia. Its persistence in the environment relies on the subtle balance between Y. pestis-contaminated soils, burrowing and nonburrowing mammals exhibiting variable degrees of plague susceptibility, and their associated fleas. Transmission from one host to another relies mainly on infected flea bites, inducing typical painful, enlarged lymph nodes referred to as buboes, followed by septicemic dissemination of the pathogen. In contrast, droplet inhalation after close contact with infected mammals induces primary pneumonic plague. Finally, the rarely reported consumption of contaminated raw meat causes pharyngeal and gastrointestinal plague. Point-of-care diagnosis, early antibiotic treatment, and confinement measures contribute to outbreak control despite residual mortality. Mandatory primary prevention relies on the active surveillance of established plague foci and ectoparasite control. Plague is acknowledged to have infected human populations for at least 5,000 years in Eurasia. Y. pestis genomes recovered from affected archaeological sites have suggested clonal evolution from a common ancestor shared with the closely related enteric pathogen Yersinia pseudotuberculosis and have indicated that ymt gene acquisition during the Bronze Age conferred Y. pestis with ectoparasite transmissibility while maintaining its enteric transmissibility. Three historic pandemics, starting in 541 AD and continuing until today, have been described. At present, the third pandemic has become largely quiescent, with hundreds of human cases being reported mainly in a few impoverished African countries, where zoonotic plague is mostly transmitted to people by rodent-associated flea bites.

A metagenomic glimpse into the gut of wild and domestic animals: Quantification of antimicrobial resistance and more

Antimicrobial resistance (AMR) in bacteria is a complex subject, why one need to look at this phenomenon from a wider and holistic perspective. The extensive use of the same antimicrobial classes in human and veterinary medicine as well as horticulture is one of the main drivers for the AMR selection. Here, we applied shotgun metagenomics to investigate the AMR epidemiology in several animal species including farm animals, which are often exposed to antimicrobial treatment opposed to an unique set of wild animals that seems not to be subjected to antimicrobial pressure. The comparison of the domestic and wild animals allowed to investigate the possible anthropogenic impact on AMR spread. Inclusion of animals with different feeding behaviors (carnivores, omnivores) enabled to further assess which AMR genes that thrives within the food chain. We tested fecal samples not only of intensively produced chickens, turkeys, and pigs, but also of wild animals such as wild boars, red foxes, and rodents. A multi-directional approach mapping obtained sequences to several databases provided insight into the occurrence of the different AMR genes. The method applied enabled also analysis of other factors that may influence AMR of intestinal microbiome such as diet. Our findings confirmed higher levels of AMR in farm animals than in wildlife. The results also revealed the potential of wildlife in the AMR dissemination. Particularly in red foxes, we found evidence of several AMR genes conferring resistance to critically important antimicrobials like quinolones and cephalosporins. In contrast, the lowest abundance of AMR was observed in rodents originating from natural environment with presumed limited exposure to antimicrobials. Shotgun metagenomics enabled us to demonstrate that discrepancies between AMR profiles found in the intestinal microbiome of various animals probably resulted from the different antimicrobial exposure, habitats, and behavior of the tested animal species.

Bartonella spp. associated with rodents in an urban protected area, Buenos Aires (Argentina)

At least 15 of the 30 Bartonella species are involved in human pathologies, and several of them are associated with rodents and their fleas. The aims of this study were detect and molecularly characterize the Bartonella infections in rodents from an urban protected area of ​Buenos Aires City (Argentina). A total of 186 rodents were captured and identified. For PCR of the 16S rRNA fragment, 23.7 % of the samples tested positive, and two groups (GrA and GrB) were identified. Likewise, the comparison between the sequences obtained for the gltA gene determined the presence of three genotypes, closely related to Bartonella spp. detected in sigmodontine rodents and their fleas in the Americas, which form a well-separated clade. The high prevalence of Bartonella in rodents from an urban protected area of ​Buenos Aires city is relevant from a public health perspective.

Occurrence and Antimicrobial Resistance Traits of Escherichia coli from Wild Birds and Rodents in Singapore

Antimicrobial resistance (AMR) in Escherichia coli (E. coli) poses a public health concern worldwide. Wild birds and rodents, due to their mobility, are potential vehicles for transmission of AMR bacteria to humans. Ninety-six wild birds’ faecal samples and 135 rodents’ droppings samples were collected and analysed in 2017. Forty-six E. coli isolates from wild birds and rodents were subjected to AMR phenotypic and genotypic characterisation. The proportion of E. coli isolates resistant to at least one of the antimicrobials tested from wild birds (80.8%) was significantly higher than that of isolates from rodents (40.0%). The proportion of E. coli isolates resistant to each antimicrobial class for wild birds was 3.8% to 73.1% and that for rodents was 5.0% to 35.0%. Six out of 26 E. coli isolates from wild birds (23.1%) and two out of 20 (10.0%) isolates from rodents were multi-drug resistant (MDR) strains. These MDR E. coli isolates were detected with various antimicrobial resistance genes such as bla_TEM-1B and qnrS1 and could be considered as part of the environmental resistome. Findings in this study suggested that wild birds and rodents could play a role in disseminating antimicrobial resistant E. coli, and this underscores the necessity of environment management and close monitoring on AMR bacteria in wild birds and rodents to prevent spreading of resistant organisms to other wildlife animals and humans.

Longitudinal Study of Bacterial Infectious Agents in a Community of Small Mammals in New Mexico

Background and Objectives: Vector-borne bacterial diseases represent a substantial public health burden and rodents have been recognized as important reservoir hosts for many zoonotic pathogens. This study investigates bacterial pathogens in a small mammal community of the southwestern United States of America. Methods: A total of 473 samples from 13 wild rodent and 1 lagomorph species were tested for pathogens of public health significance: Bartonella, Brucella, Yersinia, Borrelia, Rickettsia spp., and Anaplasma phagocytophilum. Results: Three animals were positive for Yersinia pestis, and one Sylvilagus audubonii had a novel Borrelia sp. of the relapsing fever group. No Brucella, Rickettsia, or A. phagocytophilum infections were detected. Bartonella prevalence ranged between 0% and 87.5% by animal species, with 74.3% in the predominant Neotoma micropus and 78% in the second most abundant N. albigula. The mean duration of Bartonella bacteremia in mark-recaptured N. micropus and N. albigula was 4.4 months, ranging from <1 to 18 months, and differed among Bartonella genogroups. Phylogenetic analysis of the Bartonella citrate synthase gene (gltA) revealed 9 genogroups and 13 subgroups. Seven genogroups clustered with known or previously reported Bartonella species and strains while two were distant enough to represent new Bartonella species. We report, for the first time, the detection of Bartonella alsatica in North America in Sylvilagus audubonii and expand the known host range of Bartonella washoensis to include Otospermophilus variegatus. Interpretation and Conclusion: This work broadens our knowledge of the hosts and geographic range of bacterial pathogens that could guide future surveillance efforts and improves our understanding of the dynamics of Bartonella infection in wild small mammals.

Rats as potential reservoirs for neglected zoonotic Bartonella species in Flanders, Belgium

BACKGROUND

Bartonella spp. are vector-borne pathogens transmitted to humans via blood-sucking arthropods. Rodents such as the black rat (Rattus rattus) and Norway rat (R. norvegicus) are thought to be the main reservoirs. An infection with rodent-associated Bartonella spp. may cause severe symptoms in humans such as endocarditis and neuroretinitis. The current knowledge of Bartonella prevalence in rats from western Europe is scarce.

METHODS

Rats and a few other rodent by-catches were trapped in the context of a rodenticide resistance study at different sites in Flanders, Belgium. During dissection, biometric data were collected, and spleen tissues were taken. DNA was extracted from spleen samples and tested for Bartonella spp. by conventional generic polymerase chain reaction (PCR). To determine the Bartonella species, a selected number of amplicons were sequenced and compared with GenBank entries.

RESULTS

In total, 1123 rodents were trapped. The predominate species was R. norvegicus (99.64%). Other rodents trapped included: two water voles (Arvicola amphibius, 0.18%); one colour rat (R. norvegicus forma domestica, 0.09%); and one muskrat (Ondatra zibethicus, 0.09%). PCR analysis of 1097 rodents resulted in 410 (37.37%, 95% CI: 34.50-40.31%) Bartonella spp. DNA-positive samples. Bartonella tribocorum (94.68%, 95% CI: 88.02-98.25%) was the most frequently detected Bartonella species, followed by B. grahamii (3.19%, 95% CI: 0.66-9.04%) and B. doshiae (1.06%, 95% CI: 0.03-5.79%). An uncultured Bartonella species occurred in one water vole (1.06%, 95% CI: 0.03-5.79%). There was a significantly higher Bartonella prevalence in older rats compared to juveniles and a significant difference in Bartonella prevalence concerning the localisation of trapping sites. In contrast, there was no statistically significant difference in Bartonella prevalence regarding sex, degree of urbanisation and season.

CONCLUSIONS

Based on the high prevalence found, we conclude that the Norway rat seems to be a key reservoir host for zoonotic B. tribocorum in Belgium.

Seroprevalence of leptospiral antibodies in rodents from riverside communities of Santa Fe, Argentina

Background

Leptospirosis is a zoonotic disease that can be transmitted by contact with the urine of infected mammals. Rodents play a mayor role in the transmission of leptospires to humans. The province of Santa Fe reports the greatest number of cases in Argentina. Yet, in this region, there are still knowledge gaps regarding the diversity of rodent species that may be hosts of pathogenic leptospires. The aims of this study were to evaluate the presence of leptospiral antibodies in rodents from three riverside communities of Santa Fe, and to identify factors associated with leptospiral infection.

Methodology/Principal findings

Each community was divided into three environmental settings based on the level of human disturbance, and sampled during two springs (Sep-Oct 2014 and 2015) and one autumn (Mar-Apr 2015). Serum samples of captured sigmodontine and murine rodents were tested for leptospiral antibodies by enzyme-linked immunosorbent assay (ELISA), and microagglutination test (MAT) was used to assess the infecting serovar in seropositive individuals. Factors influencing seropositivity were analyzed using logistic regression models. We caught 119 rodents, of which 101 serums were suitable for analysis. Most frequently trapped species were Scapteromys aquaticus, Akodon azarae and Oligoryzomys spp., with seroprevalences of 41.3%, 42.9% and 55% respectively. Seropositivity was higher in individuals with an average body condition score and in those that were sexually mature, but in the latter the differences were marginally significant.

Conclusions/Significance

Our results suggest that native rodents may be playing a role in the environmental circulation of pathogenic leptospires and provide relevant information for public health policies in the area.

Rodents are considered as the main reservoirs of pathogenic leptospires, which can cause leptospirosis, a disease that can be severe for both humans and domestic animals. Multiple socio-environmental factors have been found to influence the risk of leptospirosis, and many mammal species can play a role in the transmission of the bacteria. The purpose of this study was to investigate the local conditions and rodent fauna that may influence the risk of leptospirosis in communities located in the floodplains of the Parana river, near Santa Fe, Argentina. We conducted a survey of antibodies against leptospires in rodents from the center, border, and outside of three riverside settlements. We observed a relatively high seroprevalence among captured individuals (42%). Animals with an intermediate body condition were more likely to be seropositive. In most sites, native rodents were dominant over introduced rats and mice and lived close to human dwellings. Given the socio-environmental conditions observed in these settlements and the high frequency of floods that affect them, the presence of potentially infected rodents provide ample opportunities for leptospirosis to affect these communities.

The rodent vaginal microbiome across the estrous cycle and the effect of genital nerve electrical stimulation

Treatment options are limited for the approximately 40% of postmenopausal women worldwide who suffer from female sexual dysfunction (FSD). Neural stimulation has shown potential as a treatment for genital arousal FSD, however the mechanisms for its improvement are unknown. One potential cause of some cases of genital arousal FSD are changes to the composition of the vaginal microbiota, which is associated with vulvovaginal atrophy. The primary hypothesis of this study was that neural stimulation may induce healthy changes in the vaginal microbiome, thereby improving genital arousal FSD symptoms. In this study we used healthy rats, which are a common animal model for sexual function, however the rat vaginal microbiome is understudied. Thus this study also sought to examine the composition of the rat vaginal microbiota. Treatment rats (n = 5) received 30 minutes of cutaneous electrical stimulation targeting the genital branch of the pudendal nerve, and Control animals (n = 4) had 30-minute sessions without stimulation. Vaginal lavage samples were taken during a 14-day baseline period including multiple estrous periods and after twice-weekly 30-minute sessions across a six-week trial period. Analysis of 16S rRNA gene sequences was used to characterize the rat vaginal microbiota in baseline samples and determine the effect of stimulation. We found that the rat vaginal microbiota is dominated by Proteobacteria, Firmicutes, and Actinobacteria, which changed in relative abundance during the estrous cycle and in relationship to each other. While the overall stimulation effects were unclear in these healthy rats, some Treatment animals had less alteration in microbiota composition between sequential samples than Control animals, suggesting that stimulation may help stabilize the vaginal microbiome. Future studies may consider additional physiological parameters, in addition to the microbiome composition, to further examine vaginal health and the effects of stimulation.

Leptospirosis: An insight into community structure of small mammal's host in urban environment

Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira and most often acquired through contact with environments contaminated with leptospires shed in the urine of infected mammals. In urban environment, rodents are well-known as the main carriers of this bacteria, however there were no intensive study on the population structure of these animals, and how it associated with this disease. Hence, we use a case study from an outbreak in a residential area in Selangor, Malaysia, to investigate how community structure of small mammals, associated with the prevalence of Leptospira. One hundred cage traps were placed randomly in and around these houses in five phases with two months interval for a year. Community structures (species, sex, and age) were assigned for each individual, prior to screening for pathogenic Leptospira, using a partial lipL32 gene from the kidney samples. 185 small mammals from four species were captured, Rattus norvegicus (74.5%, N=138), R. rattus (20%, N=37), Tupaia glis (5%, N=9), and Suncus murinus (0.5%, N=1). From this number, 29 individuals were found PCR positive for pathogenic Leptospira (R. norvegicus, N=20; R. rattus, N=6; T. glis, N=2; S. murinus, N=1). The study shows that Leptospira occurrence in the small mammals were significantly correlated to age category and sampling phases, with Spearman Correlation (rs) p=0.02 and p=0.04 respectively. Adult individuals were significantly more prevalent with Leptospira infection, whereby March and June were found to associate with higher Leptospira prevalent among the small mammals, potentially coincide with low rainfall and relative humidity level. This information is important in designing a specific control method for rodents in Leptospira outbreak areas. In addition, intensive sampling and regular cleaning effort were found to significantly reduce the small mammal Leptospira reservoir, thus should be implemented in intervention strategies in the urban environment.

Natural diets promote retention of the native gut microbiota in captive rodents

Wild animals entering captivity experience radical lifestyle changes resulting in microbiome alterations. However, little is known about the factors that drive microbial community shifts in captivity, and what actions could mitigate microbial changes. Using white-throated woodrats (Neotoma albigula), we tested whether offering natural diets in captivity facilitates retention of native microbial communities of captive animals. Wild-caught woodrats were brought to laboratory conditions. Woodrats received either a natural diet of Opuntia cactus or an artificial diet of commercial chow over three weeks. Microbial inventories from woodrat feces at the time of capture and in captivity were generated using Illumina 16S rRNA sequencing. We found that providing woodrats with wild-natural diets significantly mitigated alterations in their microbiota, promoting a 90% retention of native microbial communities across the experiment. In contrast, the artificial diet significantly impacted microbial structure to the extent that 38% of the natural microflora was lost. Core bacteria including Bifidobacterium and Allobaculum were lost, and abundances of microbes related to oxalate degradation decreased in individuals fed artificial but not natural diets. These results highlight the importance of supplementing captive diets with natural foods to maintain native microbiomes of animals kept in artificial conditions for scientific or conservation purposes.

Contribution of glutaminases to glutamine metabolism and acid resistance in Lactobacillus reuteri and other vertebrate host adapted lactobacilli

The bacterial conversion of glutamine to glutamate is catalyzed by glutamine-amidotransferases or glutaminases. Glutamine deamination contributes to the formation of the bioactive metabolites glutamate, γ-aminobutyrate (GABA) and γ-glutamyl peptides, and to acid resistance. This study aimed to investigate the distribution of glutaminase(s) in lactobacilli, and to evaluate their contribution in L. reuteri to amino acid metabolism and acid resistance. Phylogenetic analysis of the glutaminases gls1, gls2 and gls3 in the genus Lactobacillus demonstrated that glutaminase is exclusively present in host-adapted species of lactobacilli. The disruption gls1, gls2 and gls3 in L. reuteri 100-23 had only a limited effect on the conversion of glutamine to glutamate, GABA, or γ-glutamyl peptides in sourdough. The disruption of all glutaminases in L. reuteri 100-23Δgls1Δgls2Δgls3 but not disruption of gls2 and gls3 eliminated the protective effect of glutamine on the survival of the strain at pH 2.5. Glutamine also enhanced acid resistance of L. reuteri 100-23ΔgadB and L. taiwanensis 107q, strains without glutamate decarboxylase activity. Taken together, the study demonstrates that glutaminases of lactobacilli do not contribute substantially to glutamine metabolism but enhance acid resistance. Their exclusive presence in host-adapted lactobacilli provides an additional link between the adaptation of lactobacilli to specific habitats and their functionality when used as probiotics and starter cultures.

Seroprevalence, Risk Factors, and Rodent Reservoirs of Leptospirosis in an Urban Community of Puerto Rico, 2015

BACKGROUND

The burden of leptospirosis in Puerto Rico remains unclear due to underreporting.

METHODS

A cross-sectional survey and rodent trapping was performed in a community within San Juan, Puerto Rico to determine the seroprevalence and risk factors for Leptospira infection. The microscopic agglutination test was used to detect anti-Leptospira antibodies as a marker of previous infection. We evaluated Leptospira carriage by quantitative polymerase chain reaction among rodents trapped at the community site.

RESULTS

Of 202 study participants, 55 (27.2%) had Leptospira agglutinating antibodies. Among the 55 seropositive individuals, antibodies were directed most frequently against serogroups Icterohaemorrhagiae (22.0%) and Autumnalis (10.6%). Of 18 captured rodents, 11 (61.1%) carried pathogenic Leptospira (Leptospira borgpetersenii, 7 and Leptospira interrogans, 2). Four participants showed their highest titer against an isolate obtained from a rodent (serogroup Ballum). Increasing household distance to the canal that runs through the community was associated with decreased risk of infection (odds ratio = 0.934 per 10-meter increase; 95% confidence interval, .952-.992).

CONCLUSIONS

There are high levels of Leptospira exposure in an urban setting in Puerto Rico, for which rodents may be an important reservoir for transmission. Our findings indicate that prevention should focus on mitigating risk posed by infrastructure deficiencies such as the canal.

Risk factors for acquisition of scrub typhus in children admitted to a tertiary centre and its surrounding districts in South India: a case control study

BACKGROUND

Scrub typhus is a mite borne zoonosis common in the tropics with no good preventive strategy. Children are also affected leading to considerable morbidity and mortality. We conducted a case control study and a vector survey to determine the risk factors for acquisition of scrub typhus.

METHODS

A case control study with a 1:2 case control ratio was conducted over a 2 year period at a tertiary care centre and its surrounding districts in South India. Cases were children < 15 years with confirmed scrub typhus. Controls were age and locality matched community controls without fever. Demographic, environmental and behavioural risk factors were obtained in cases and controls by an interview and an environmental survey. A vector survey was also undertaken in the immediate vicinity of the cases.

RESULTS

Case Control study: 101 cases and 167 controls were analysed. On multivariate analysis, significant association was observed with environmental factors such as the presence of a water body within 100 m of the house (OR 3.56(1.36,9.75); p 0.011), cooking outside the house (OR 5.61 (1.51,23.01); p 0.011), owning pets (OR 3.33(1.16,9.09); p 0.031), and the presence of bushes within 5 m of the house (OR 2.78 (1.11,7.69); p 0.033). Of the behavioural factors, the child going to school by a vehicle (OR 3.12 (2.29,8.37); p 0.006) was associated with an increased risk. Drying clothes on a clothesline showed a trend towards protection from acquiring scrub typhus (OR 0.31 (0.08, 1.08); p 0.077). Vector survey:26 rodents were trapped in as many houses. Trombiculid mites were isolated in 24 houses with 9(34.6%) being able to transmit scrub typhus. 254 trombiculid mites belonging to four species and two genera were collected. Leptotrombidium deliense, (33.5%). Schoengastiella ligula, (11.0%) of the total mite specimens collected. S. ligula always co-existed with L. deliense. The estimated Chigger index for Leptotrombidium deliense and Schoengastiella ligula was 3.27and 1.08 per animal respectively.

CONCLUSIONS

Our study highlights risk factors for scrub typhus, some of which may be modifiable. A clean peri-domestic environment free of vegetation, drying clothes on a clothesline and cooking indoors may decrease the risk of scrub typhus.

Streptococcus castoreus, an uncommon group A Streptococcus in beavers

Streptococcus castoreus is a rarely encountered beta-haemolytic group A Streptococcus with high tropism for the beaver as host. Based on 27 field isolates under study, evidence strongly suggests that S. castoreus behaves as an opportunistic pathogen in beavers. Although it belongs to the resident mucosal microbiota, this Streptococcus species is associated with purulent lesions in diseased animals. With few exceptions, isolates proved to be highly similar in a panel of phenotypic (including biochemistry, resistance pattern, MALDI-TOF mass spectrometry and Fourier transform-infrared spectroscopy) and classic molecular (16S rRNA and sodA gene) analyses, and thus did not show any specific pattern according to host species or spatio-temporal origin. Conversely, S. castoreus isolates were differentiated into a multitude of pulsed-field gel electrophoresis 'pulsotypes' that did not seem to reflect true epidemiologic lineages. In contrast, single reactions of genomic fingerprinting using BOX-, (GTG)₅- and RAPD-PCRs revealed at least subclusters with respect to host species, geographic origin or year, and confirmed the co-colonization of individuals with more than one isolate. In addition to isolates from free-ranging Eurasian beavers (Castor fiber), this study includes S. castoreus from captive North American beavers (Castor canadensis) for the first time.

Microhabitat Factors Influenced the Prevalence of Pathogenic Leptospira spp. in Small Mammal Host

Leptospirosis, a widespread zoonotic disease, is a public health problem, especially in major urban centres, and is mainly reported to be associated with rats. In Malaysia, focus has been primarily given to the Leptospira prevalence in rodents per se, but there is lack of information on the microhabitat structure of the outbreak areas. We aimed to determine the diversity of small mammal species, microhabitat types, and their prevalence of pathogenic Leptospira spp. in the outbreak areas, which were categorized as urban, semi-urban, and recreational forests. Sampling involved deploying 100 to 300 live traps at each study site. Kidney samples were extracted from selected individuals, for screening of pathogenic Leptospira spp. by PCR. Out of 537 individuals from 15 small mammal species captured, 4 species were recorded from urban, 13 from semi-urban, and 11 from recreational forest sites. From 389 individuals screened, 58 were tested positive for pathogenic Leptospira. Recreational forests recorded the highest prevalence with 19.4% (n = 93), followed by urban, 16.6% (n = 163) and semi-urban sites with 9.8% (n = 133). Seven rodent species were tested positive for pathogenic Leptospira from all areas. R. norvegicus was found to harbour the highest prevalence (66.7%) in urban, R. rattus (53.8%) in semi-urban, whereby M. whiteheadi (44.4%) in recreational forest sites. Microhabitat analysis revealed that rubbish quantity contributed especially strongly to a high prevalence of Leptospira. This study contributes to understanding of the host and microhabitat preferences of Leptospira, which is important in controlling the spread of this disease in human's landscapes.

Living with plague: Lessons from the Soviet Union's antiplague system

Zoonoses, such as plague, are primarily animal diseases that spill over into human populations. While the goal of eradicating such diseases is enticing, historical experience validates abandoning eradication in favor of ecologically based control strategies (which reduce morbidity and mortality to a locally accepted risk level). During the 20th century, one of the most extensive plague-eradication efforts in recorded history was undertaken to enable large-scale changes in land use in the former Soviet Union (including vast areas of central Asia). Despite expending tremendous resources in its attempt to eradicate plague, the Soviet antiplague response gradually abandoned the goal of eradication in favor of plague control linked with developing basic knowledge of plague ecology. Drawing from this experience, we combine new gray-literature sources, historical and recent research, and fieldwork to outline best practices for the control of spillover from zoonoses while minimally disrupting wildlife ecosystems, and we briefly compare the Soviet case with that of endemic plague in the western United States. We argue for the allocation of sufficient resources to maintain ongoing local surveillance, education, and targeted control measures; to incorporate novel technologies selectively; and to use ecological research to inform developing landscape-based models for transmission interruption. We conclude that living with emergent and reemergent zoonotic diseases-switching to control-opens wider possibilities for interrupting spillover while preserving natural ecosystems, encouraging adaptation to local conditions, and using technological tools judiciously and in a cost-effective way.

The prevalence of Leptospira among invasive small mammals on Puerto Rican cattle farms

Leptospirosis, an emerging infectious disease caused by bacteria of the genus Leptospira, is thought to be the most widespread zoonotic disease in the world. A first step in preventing the spread of Leptospira is delineating the animal reservoirs that maintain and disperse the bacteria. Quantitative PCR (qPCR) methods targeting the LipL32 gene were used to analyze kidney samples from 124 House mice (Mus musculus), 94 Black rats (Rattus rattus), 5 Norway rats (R. norvegicus), and 89 small Indian mongooses (Herpestes auropunctatus) from five cattle farms in Puerto Rico. Renal carriage of Leptospira was found in 38% of the sampled individuals, with 59% of the sampled mice, 34% of Black rats, 20% of Norway rats, and 13% of the mongooses. A heterogeneous distribution of prevalence was also found among sites, with the highest prevalence of Leptospira-positive samples at 52% and the lowest at 30%. Comparative sequence analysis of the LipL32 gene from positive samples revealed the presence of two species of Leptospira, L. borgpetersenii and L. interrogans in mice, detected in similar percentages in samples from four farms, while samples from the fifth farm almost exclusively harbored L. interrogans. In rats, both Leptospira species were found, while mongooses only harbored L. interrogans. Numbers tested for both animals, however, were too small (n = 7 each) to relate prevalence of Leptospira species to location. Significant associations of Leptospira prevalence with anthropogenic landscape features were observed at farms in Naguabo and Sabana Grande, where infected individuals were closer to human dwellings, milking barns, and ponds than were uninfected individuals. These results show that rural areas of Puerto Rico are in need of management and longitudinal surveillance of Leptospira in order to prevent continued infection of focal susceptible species (i.e. humans and cattle).

Rodent-borne infections in rural Ghanaian farming communities

Rodents serve as reservoirs and/or vectors for several human infections of high morbidity and mortality in the tropics. Population growth and demographic shifts over the years have increased contact with these mammals, thereby increasing opportunities for disease transmission. In Africa, the burden of rodent-borne diseases is not well described. To investigate human seroprevalence of selected rodent-borne pathogens, sera from 657 healthy adults in ten rural communities in Ghana were analyzed. An in-house enzyme-linked immunosorbent assay (ELISA), for immunoglobulin G (IgG) antibodies to Lassa virus was positive in 34 (5%) of the human samples. Using commercial kits, antibodies to hantavirus serotypes, Puumala and Dobrava, and Leptospira bacteria were detected in 11%, 12% and 21% of the human samples, respectively. Forty percent of residents in rural farming communities in Ghana have measurable antibodies to at least one of the rodent-borne pathogens tested, including antibodies to viral hemorrhagic fever viruses. The high seroprevalence found in rural Ghana to rodent-borne pathogens associated with both sporadic cases and larger disease outbreaks will help define disease threats and inform public health policy to reduce disease burden in underserved populations and deter larger outbreaks.

Long-term trends of tick-borne pathogens in regard to small mammal and tick populations from Saxony, Germany

BACKGROUND

Rodents are important in the life-cycle of ticks as hosts for immature developmental stages. Both rodents and ticks are of public health interest as they are reservoirs and vectors for different tick-borne pathogens (TBP). The aim of this study was to reassess the prevalence of TBP in previously studied areas of the city of Leipzig (Saxony, Germany).

METHODS

In the years 2015-2017 rodents and ticks were collected in parks and forest areas in Saxony. DNA was extracted from the rodents, attached and questing ticks. Samples were screened for the presence of Anaplasma phagocytophilum, Babesia spp., Borrelia burgdorferi (s.l.), "Candidatus Neoehrlichia mikurensis" (CNM), Bartonella spp., Hepatozoon spp. and Rickettsia spp. using PCR methods. Rodent, attached nymph and questing tick (nymph and adult) samples were tested individually, while attached larvae were further processed in pools.

RESULTS

A total of 165 rodents (Apodemus agrarius, n = 1; A. flavicollis, n = 59; Arvicola terrestris, n = 1; Myodes glareolus, n = 104), 1256 attached ticks (Ixodes ricinus, n = 1164; Dermacentor reticulatus, n = 92) and 577 questing ticks (I. ricinus, n = 547; D. reticulatus, n = 30) were collected. The prevalence levels in rodents were 78.2% for Bartonella spp., 58.2% for CNM, 49.1% for B. burgdorferi (s.l.) 29.1% for Rickettsia spp. and 24.2% for Hepatozoon spp. The minimal infection rates (MIR) in attached larvae ticks were 39.8% for Rickettsia spp., 32.7% for Bartonella spp., 7.1% for CNM and 8.8% for B. burgdorferi (s.l.) and the prevalence rates in attached nymphs were 33.7% for Bartonella spp., 52.9% for Rickettsia spp., 13.5% for CNM and 11.3% for B. burgdorferi (s.l.) Both rodents and attached ticks were negative for Babesia spp. The prevalence in questing ticks was 18.2% for Rickettsia spp., 7.3% for CNM, 6.4% for B. burgdorferi (s.l.) and 1.4% for Babesia spp. All tested samples were Anaplasma-negative. Sequencing revealed the occurrence of 14 identified species.

CONCLUSIONS

This research is the first evaluation of the prevalence for Hepatozoon spp. in rodents from Germany. In comparison to earlier studies, detected pathogens species remained the same; however, the prevalence for particular pathogens differed.

Anthropogenic environmental drivers of antimicrobial resistance in wildlife

The isolation of antimicrobial resistant bacteria (ARB) from wildlife living adjacent to humans has led to the suggestion that such antimicrobial resistance (AMR) is anthropogenically driven by exposure to antimicrobials and ARB. However, ARB have also been detected in wildlife living in areas without interaction with humans. Here, we investigated patterns of resistance in Escherichia coli isolated from 408 wild bird and mammal faecal samples. AMR and multi-drug resistance (MDR) prevalence in wildlife samples differed significantly between a Sewage Treatment Plant (STP; wastes of antibiotic-treated humans) and a Farm site (antibiotic-treated livestock wastes) and Central site (no sources of wastes containing anthropogenic AMR or antimicrobials), but patterns of resistance also varied significantly over time and between mammals and birds. Over 30% of AMR isolates were resistant to colistin, a last-resort antibiotic, but resistance was not due to the mcr-1 gene. ESBL and AmpC activity were common in isolates from mammals. Wildlife were, therefore, harbouring resistance of clinical relevance. AMR E. coli, including MDR, were found in diverse wildlife species, and the patterns and prevalence of resistance were not consistently associated with site and therefore different exposure risks. We conclude that AMR in commensal bacteria of wildlife is not driven simply by anthropogenic factors, and, in practical terms, this may limit the utility of wildlife as sentinels of spatial variation in the transmission of environmental AMR.

Distribution of Orientia tsutsugamushi in rodents and mites collected from Central India

Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracytosolic bacterium transmitted among humans and small mammals by some species of larval trombiculid mites (chiggers). It has been recognized as a pathogen of major public health concern in the Asia-Pacific region. As disease is considered as a neglected, there exists a gap in our knowledge of the disease with regard to the sporadic epidemiologic data in endemic areas. The purpose of the study was to find out the vector as well as pathogen distribution in rodents present in the scrub typhus-reported areas in central India. We studied the seasonal variations of occurrence in O. tsutsugamushi in rodents and mites by molecular detection targeting the 56-kDa and 47-kDa genes. Rodent and mite samples were collected during December 2015 to July 2017. A total of 127 samples from rodents, seven pools of mites, and four pools of fleas were collected and processed for DNA isolation. Nested PCRs targeting the 56-kDa and 47-kDa surface antigen genes were performed. In addition, quantification of bacterial load was done by qPCR targeting the 47-kDa gene. During the pre-monsoon season, O. tsutsugamushi was detected in 12% and 10% samples employing the 56-kDa and 47-kDa nested PCRs, respectively, whereas, during post-monsoon season, the respective detection rates were 13.33% and 26.66%. This study predicted a bimodal pattern during the months of pre-monsoon and post-monsoon season with a peak in post-monsoon. Thus, the impact of season on the perpetuation of O. tsutsugamushi in the host was observed.

Long-Term Study of a Hantavirus Reservoir Population in an Urban Protected Area, Argentina

Green spaces in urban areas can play a key role in protecting wildlife. However, the presence of wildlife in urban areas can lead to human health risks. Although the presence of the rodent species Oligoryzomys flavescens (hantavirus reservoir) has been recorded in cities of Argentina, its population dynamics in this type of habitat is still unknown. Here, we evaluated: (1) long-term spatial and temporal patterns of O. flavescens abundance and how these patterns were influenced by weather factors and (2) the seroprevalence of hantavirus and the identity of the viral lineage circulating in the population that inhabits the Costanera Sur Ecological Reserve, a protected area in the city of Buenos Aires. Genetic results confirmed that the pathogenic ANDES Central Lechiguanas virus is present in O. flavescens populations inhabiting this urban reserve. Abundance of O. flavescens showed interannual and seasonal fluctuations, with maximum values in winter and spring and minimum ones in summer and autumn. Summers with the highest abundances of O. flavescens were preceded by warmer winters, while winters with lower abundances were preceded by warmer summers. On the other hand, accumulated precipitations in the previous 6 months positively affected winter abundance. These results could help the authorities in charge of the green spaces of Buenos Aires to identify priority areas and times of the year for the implementation of preventive measures that minimize the contact of rodents with visitors. Such measures could be intensified when winters are warmer than normal, and summers are cooler and wetter than normal.

Global fingerprint of humans on the distribution of Bartonella bacteria in mammals

As humans move and alter habitats, they change the disease risk for themselves, their commensal animals and wildlife. Bartonella bacteria are prevalent in mammals and cause numerous human infections. Understanding how this genus has evolved and switched hosts in the past can reveal how current patterns were established and identify potential mechanisms for future cross-species transmission. We analyzed patterns of Bartonella transmission and likely sources of spillover using the largest collection of Bartonella gltA genotypes assembled, including 67 new genotypes. This pathogenic genus likely originated as an environmental bacterium and insect commensal before infecting mammals. Rodents and domestic animals serve as the reservoirs or at least key proximate host for most Bartonella genotypes in humans. We also find evidence of exchange of Bartonella between phylogenetically distant domestic animals and wildlife, likely due to increased contact. Care should be taken to avoid contact between humans, domestic animals and wildlife to protect the health of all.

As humans move around the globe they contact new environments, potentially introducing novel diseases to wildlife, domestic animals and humans. Understanding how current infection patterns were established and how humans have likely altered them can help protect human, animal and environmental health. We traced the evolution of and distribution of globally distributed, pathogenic Bartonella, a common and well-studied bacterial genus in wildlife and humans that can cause cat scratch disease, trench fever and other diseases. We showed that humans are likely changing disease risk for themselves and the animals in their environment by moving themselves and domestic animals, as evidenced by large geographic movements of infections or shared infections in distantly related species. Not only does this increase our knowledge about Bartonella, an important emerging pathogen, but our investigation can serve as a model for elucidating the driving role of humans in changing disease landscapes.

Identification of Leptospira and Bartonella among rodents collected across a habitat disturbance gradient along the Inter-Oceanic Highway in the southern Amazon Basin of Peru

Background

The southern Amazon Basin in the Madre de Dios region of Peru has undergone rapid deforestation and habitat disruption, leading to an unknown zoonotic risk to the growing communities in the area.

Methodology/Principal findings

We surveyed the prevalence of rodent-borne Leptospira and Bartonella, as well as potential environmental sources of human exposure to Leptospira, in 4 communities along the Inter-Oceanic Highway in Madre de Dios. During the rainy and dry seasons of 2014–2015, we captured a total of 97 rodents representing 8 genera in areas that had experienced different degrees of habitat disturbance. Primarily by using 16S metagenomic sequencing, we found that most of the rodents (78%) tested positive for Bartonella, whereas 24% were positive for Leptospira; however, the patterns differed across seasons and the extent of habitat disruption. A high prevalence of Bartonella was identified in animals captured across both trapping seasons (72%–83%) and the relative abundance was correlated with increasing level of land disturbance. Leptospira-positive animals were more than twice as prevalent during the rainy season (37%) as during the dry season (14%). A seasonal fluctuation across the rainy, dry, and mid seasons was also apparent in environmental samples tested for Leptospira (range, 55%–89% of samples testing positive), and there was a high prevalence of this bacteria across all sites that were sampled in the communities.

Conclusions/Significance

These data indicate the need for increased awareness of rodent-borne disease and the potential for environmental spread along the communities in areas undergoing significant land-use change.

Genetic Diversity of Bartonella spp. in Wild Mammals and Ectoparasites in Brazilian Pantanal

The present work aimed to investigate the genetic diversity of Bartonella in mammals and ectoparasites in Pantanal wetland, Brazil. For this purpose, 31 Nasua nasua, 78 Cerdocyon thous, 7 Leopardus pardalis, 110 wild rodents, 30 marsupials, and 42 dogs were sampled. DNA samples were submitted to a quantitative real-time PCR assay (qPCR). Positive samples in qPCR were submitted to conventional PCR assays targeting other five protein-coding genes. Thirty-five wild rodents and three Polygenis (P.) bohlsi bohlsi flea pools showed positive results in qPCR for Bartonella spp. Thirty-seven out of 38 positive samples in qPCR were also positive in cPCR assays based on ftsZ gene, nine in nuoG-cPCR, and six in gltA-cPCR. Concatenated phylogenetic analyses showed that two main genotypes circulate in rodents and ectoparasites in the studied region. While one of them was closely related to Bartonella spp. previously detected in Cricetidae rodents from North America and Brazil, the other one was related to Bartonella alsatica, Bartonella pachyuromydis, Bartonella birtlesii, Bartonella acomydis, Bartonella silvatica, and Bartonella callosciuri. These results showed that at least two Bartonella genotypes circulate among wild rodents. Additionally, the present study suggests that Polygenis (P.) bohlsi bohlsi fleas could act as possible Bartonella vectors among rodents in Pantanal wetland, Brazil.

Prevalence and diversity of Rickettsia species in ectoparasites collected from small rodents in Lithuania

BACKGROUND

Rickettsiae are emerging pathogens causing public health problems in many countries around the world. Rickettsia spp. are found in association with a wide range of arthropods which feed on different species of animals. However, the distribution and natural cycle of Rickettsia species and their association with different arthropod vectors are not fully established. The aim of this study was to investigate the presence and prevalence of Rickettsia spp. in ticks, mites and fleas parasitizing different species of small mammals in Lithuania and to molecularly characterize the Rickettsia spp. obtained from different ectoparasites.

RESULTS

A total of 1261 ectoparasites (596 Ixodes ricinus ticks, 550 mites of five species and 115 fleas of eight species) collected from 238 rodents in Lithuania during 2013-2014 were investigated for the presence of Rickettsia pathogens. Infection rates were calculated as the maximum likelihood estimation (MLE) with 95% confidence intervals (CI). The infection rate varied among ectoparasites and was found highest in fleas 43.5%, followed by I. ricinus ticks (MLE = 26.5%; 95% CI: 22.2-31.3%) and then mites (MLE = 9.3%; 95% CI: 7.0-12.2%). Sequence analysis of partial gltA and 17kDa genes revealed the presence of Rickettsia helvetica, R. felis, R. monacensis, Rickettsia sp. and rickettsial endosymbionts. Four Rickettsia spp. were identified in fleas, while three Rickettsia spp. were identified in Laelapidae mites and only one (R. helvetica) in I. ricinus ticks.

CONCLUSIONS

To our knowledge, this is the first report of the occurrence and molecular characterization of Rickettsia spp. in 11 species of ectoparasites of small rodents in Lithuania. The present data extend the knowledge on the distribution of Rickettsia spp. and their association with different arthropod vectors. Prior to our study, R. felis had never been identified in Lithuania. To our knowledge, this is also the first report of R. felis in L. agilis and H. microti mites and in Ct. agyrtes and H. talpae fleas, as well as the first detection of R. monacensis in Ct. agyrtes fleas.

Assessment of animal hosts of pathogenic Leptospira in northern Tanzania

Leptospirosis is a zoonotic bacterial disease that affects more than one million people worldwide each year. Human infection is acquired through direct or indirect contact with the urine of an infected animal. A wide range of animals including rodents and livestock may shed Leptospira bacteria and act as a source of infection for people. In the Kilimanjaro Region of northern Tanzania, leptospirosis is an important cause of acute febrile illness, yet relatively little is known about animal hosts of Leptospira infection in this area. The roles of rodents and ruminant livestock in the epidemiology of leptospirosis were evaluated through two linked studies. A cross-sectional study of peri-domestic rodents performed in two districts with a high reported incidence of human leptospirosis found no evidence of Leptospira infection among rodent species trapped in and around randomly selected households. In contrast, pathogenic Leptospira infection was detected in 7.08% cattle (n = 452 [5.1-9.8%]), 1.20% goats (n = 167 [0.3-4.3%]) and 1.12% sheep (n = 89 [0.1-60.0%]) sampled in local slaughterhouses. Four Leptospira genotypes were detected in livestock. Two distinct clades of L. borgpetersenii were identified in cattle as well as a clade of novel secY sequences that showed only 95% identity to known Leptospira sequences. Identical L. kirschneri sequences were obtained from qPCR-positive kidney samples from cattle, sheep and goats. These results indicate that ruminant livestock are important hosts of Leptospira in northern Tanzania. Infected livestock may act as a source of Leptospira infection for people. Additional work is needed to understand the role of livestock in the maintenance and transmission of Leptospira infection in this region and to examine linkages between human and livestock infections.

The Mammary Microenvironment in Mastitis in Humans, Dairy Ruminants, Rabbits and Rodents: A One Health Focus

The One Health concept promotes integrated evaluation of human, animal, and environmental health questions to expedite advances benefiting all species. A recognition of the multi-species impact of mastitis as a painful condition with welfare implications leads us to suggest that mastitis is an ideal target for a One Health approach. In this review, we will evaluate the role of the mammary microenvironment in mastitis in humans, ruminants and rabbits, where appropriate also drawing on studies utilising laboratory animal models. We will examine subclinical mastitis, clinical lactational mastitis, and involution-associated, or dry period, mastitis, highlighting important anatomical and immunological species differences. We will synthesise knowledge gained across different species, comparing and contrasting disease presentation. Subclinical mastitis (SCM) is characterised by elevated Na/K ratio, and increased milk IL-8 concentrations. SCM affecting the breastfeeding mother may result in modulation of infant mucosal immune system development, whilst in ruminants notable milk production losses may ensue. In the case of clinical lactational mastitis, we will focus on mastitis caused by Staphylococcus aureus and Escherichia coli. Understanding of the pathogenesis of involution-associated mastitis requires characterization of the structural and molecular changes occurring during involution and we will review these changes across species. We speculate that milk accumulation may act as a nidus for infection, and that the involution 'wound healing phenotype' may render the tissue susceptible to bacterial infection. We will discuss the impact of concurrent pregnancy and a 'parallel pregnancy and involution signature' during bovine mammary involution.

Dembo polymerase chain reaction technique for detection of bovine abortion, diarrhea, and respiratory disease complex infectious agents in potential vectors and reservoirs

Bovine abortion, diarrhea, and respiratory disease complexes, caused by infectious agents, result in high and significant economic losses for the cattle industry. These pathogens are likely transmitted by various vectors and reservoirs including insects, birds, and rodents. However, experimental data supporting this possibility are scarce. We collected 117 samples and screened them for 44 bovine abortive, diarrheal, and respiratory disease complex pathogens by using Dembo polymerase chain reaction (PCR), which is based on TaqMan real-time PCR. Fifty-seven samples were positive for at least one pathogen, including bovine viral diarrhea virus, bovine enterovirus, Salmonella enterica ser. Dublin, Salmonella enterica ser. Typhimurium, and Neospora caninum; some samples were positive for multiple pathogens. Bovine viral diarrhea virus and bovine enterovirus were the most frequently detected pathogens, especially in flies, suggesting an important role of flies in the transmission of these viruses. Additionally, we detected the N. caninum genome from a cockroach sample for the first time. Our data suggest that insects (particularly flies), birds, and rodents are potential vectors and reservoirs of abortion, diarrhea, and respiratory infectious agents, and that they may transmit more than one pathogen at the same time.

Ten years of surveillance of the Yulong plague focus in China and the molecular typing and source tracing of the isolates

Plague, caused by Yersinia pestis, was classified as a reemerging infectious disease by the World Health Organization. The five human pneumonic plague cases in Yulong County in 2005 gave rise to the discovery of a Yulong plague focus in Yunnan province, China. Thereafter, continuous wild rodent plague (sylvatic plague) was identified as the main plague reservoir of this focus. In this study, the epizootics in Yulong focus were described, and three molecular typing methods, including the different region (DFR) analysis, clustered regularly interspaced short palindromic repeats (CRISPRs), and the multiple-locus variable number of tandem repeats (VNTR) analysis (MLVA) (14+12), were used for the molecular typing and source tracing of Y. pestis isolates in the Yulong plague focus. Simultaneously, several isolates from the vicinity of Yunnan were used as controls. The results showed that during the 10-year period from 2006 to 2016, an animal plague epidemic occurred in 6 of those years, and 5 villages underwent an animal plague epidemic within a 30-km² area of the Yulong plague focus. Searching for dead mice was the most effective monitoring method in this plague focus. No positive sample has been found in 6937 captured live rodents thus far, suggesting that the virulence of strains in the Yulong plague focus is stronger and the survival time of mice is shorter after infection. Strains from Lijiang, Sichuan and Tibet were of the same complex based on a typing analysis of DFR and CRISPR. The genetic relationship of Y. pestis illustrated by MLVA “14+12” demonstrates that Tibet and Sichuan strains evolved from the strains 1.IN2 (Qinghai, 1970 and Tibet, 1976), and Lijiang strains are closer to Batang strains (Batang County in Sichuan province, 2011, Himalaya marmot plague foci) in terms of genetic or phylogenic relationships. In conclusion, we have a deeper understanding of this new plague focus throughout this study, which provides a basis for effective prevention and control.

Plague is a type of zoonosis that is highly lethal to humans. The surveillance of animal hosts is critical for the prevention and control of plague. The Yulong plague focus is a newly discovered plague focus in China in recent years. The plague outbreak had attracted widespread attention because 5 people were infected in 2005, 2 of whom died. We have monitored the plague focus for a decade, and isolated strains and DNAs of Yersinia pestis were studied. The structure, origin and evolutionary trend of the Yulong plague focus were clarified, which provides a scientific basis for the effective prevention and control of human plague. This article also provides a set of paradigms for the systematic study of new plague foci, which is a perfect combination of traditional monitoring methods and modern research methods.