Ticks, mites, fleas, and vector-borne pathogens in free-ranging neotropical wild felids from southern Brazil

New records of fleas and ticks (Siphonaptera and Ixodida) parasitizing wild mammals in Mossoró Municipality, Rio Grande do Norte State, Brazil

The Caatinga is a Brazilian biome with limited studies on its wild mammal fauna, including the ectoparasitic relationships in these animals. This study aims to report the findings of fleas and ticks infesting wild animals rescued in the municipality of Mossoró, Rio Grande do Norte State (RN), Brazil, and treated at the Veterinary Hospital of the Universidade Federal Rural do Semi-Árido (HOVET-UFERSA). During the clinical assessments and physical examinations of the host animals (one male Cerdocyon thous L.; two females of Tamandua tetradactyla L.; one male Leopardus tigrinus Schreber; and one male Conepatus semistriatus Boddaert), fleas and ticks were collected. These ectoparasites were removed mechanically and sent to the Animal Parasitology Laboratory at UFERSA for identification. Identification was carried out based on morphology, with the aid of specific literature, stereomicroscopy, and light optical microscopy. From C. thous, two males of Amblyomma parvum Aragão and four female Pulex irritans (L.) fleas were recovered. From the adult female T. tetradactyla, one male of Rhipicephalus linnaei (Audouin), eight nymphs, and two males of Amblyomma auricularium (Conil) were collected. From the juvenile female T. tetradactyla, three nymphs of A. parvum and six female fleas of the species Tunga penetrans (L.) were recovered. From the male L. tigrinus, five females and one male flea of the species Ctenocephalides felis (Bouche) were collected. Finally, from the male C. semistriatus, two nymphs, 19 males, and six females of A. auricularium were recovered. This study contributes to expanding the knowledge of host-parasite relationships in free-living mammals in the Caatinga biome, in western Rio Grande do Norte.

Brazilian fleas (Hexapoda: Siphonaptera): diversity, host associations, and new records on small mammals from the Atlantic Rainforest, including Rickettsia screening

BACKGROUND

Insects belonging to the Siphonaptera order are obligatory ectoparasites of vertebrates, including humans. Their life cycle is marked by holometabolous development, and adults are adapted to have a bloodmeal out of their hosts. The objective of this study is to review the families occurring in Brazil with their species and report new records from fleas collected in an Atlantic Rainforest preserved area, including Rickettsia sp. monitoring.

METHODS

Literature research was carried out, including journal articles and books available in scientific databases. The sample collection took place at Legado das Águas-Reserva Votorantim private reserve, where wild rodents, marsupials, and bats were captured and inspected for the presence of fleas. The fleas were identified, and their genetic material was extracted and subjected to two polymerase chain reactions (PCRs): an endogenous control to validate the extraction and a Rickettsia screening.

RESULTS

A total of 8 families were reviewed, resulting in 63 valid species that interact with a wide range of hosts. Among the collected fleas, 7 species were identified as interacting with 19 different host genera belonging to the Rodentia, Didelphimorphia, and Chiroptera orders. We highlight the presence of 2 new locality records and 15 new host interactions. Of the collected fleas, 105 specimens were tested individually for Rickettsia bacteria, but none showed expected amplicons for the bacterium.

CONCLUSIONS

This study provides an extensive revision of the Siphonaptera order present in Brazil with new insights, since the last robust revision made was from 2000, along with new information regarding host association and locality based on field collections conducted by the authors, which helps understanding the host-parasite interaction and encourages new studies.

Natural infection and diversity of hemotropic mycoplasmas in free-ranging Geoffroy's cat (Leopardus geoffroyi) and margay cat (Leopardus wiedii) populations in Southern Brazil

Hemoplasma infection significantly impacts felines health, yet there is a research gap regarding free-ranging wild small felids. Therefore, this study aimed to investigate the occurrence of hemoplasma in Leopardus geoffroyi and Leopardus wiedii in southern Brazil. For this purpose, we conducted molecular research for Mycoplasma spp. based on the 16S rRNA gene in 79 blood samples from captured wild felids. When positive, the samples were submitted to species-specific reactions for Mycoplasma haemofelis (Mhf), 'Candidatus Mycoplasma haemominutum' (CMhm), and 'Candidatus Mycoplasma turicensis' (CMt). A total of 39/79 samples were positive for at least one species of hemoplasma. The frequencies found by hemoplasma species were: 39.2 % (31/79) for Mhf, 17.7 % (14/79) for CMhm, and 20.2 % (16/79) for CMt. Factors such as species, sex, age, pelage, capture season, ectoparasite presence, and co-infection with another Mycoplasma were not associated with hemoplasma infection. This study provides the first evidence of circulating hemotropic mycoplasmas in free-living L. geoffroyi and L. wiedii in southern Brazil.

A "One health" approach to the understanding of mammals, ticks and Rickettsia interactions in the Andes of Colombia

Infectious diseases, especially zoonotic, represent a significant global threat to both human and animal health. Ticks are among the primary vectors of pathogens affecting wild and domestic animals, some of which can also cause severe human diseases. To effectively face zoonotic diseases, the "One Health" approach is being promoted to integrate the health of human, animals, and ecosystems. Here, we identify the associations between ticks, rickettsiae, wild and domestic mammals, and humans in the Andean region of Colombia. A total of 366 ticks of 17 species belonging to the genera Amblyomma, Dermacentor, Ixodes, Ornithodoros, and Rhipicephalus were collected as free-living organisms, or parasitizing humans, wild (22 species) and domestic (3 species) mammals. Infection with Rickettsia parkeri strain NOD, Rickettsia cf. monacensis and 'Candidatus Rickettsia tarasevichiae' was detected in 3.4% of the ticks analyzed (n = 3). This study highlights the diversity of ticks in humans and wild and domestic mammals in Colombia. It also underscores the risk these ectoparasites represent to human and animal health due to the potential transmission of zoonotic pathogens such as Rickettsia spp.

New records of endoparasites and ectoparasites in free-living road-killed wild animals in the Pampa biome, Southern Brazil

Wild animals host a wide variety of parasites, and the disorders caused by these parasites are among the most prevalent and significant infectious diseases affecting wildlife. The investigation of parasitic fauna is crucial for the conservation of wild animals, domestic populations, and humans. Therefore, the aim of the study was to survey endo- and ectoparasites in free-living wildlife in southern Brazil. Carcasses of road-killed wildlife were collected from highways in the Pelotas microregion, Rio Grande do Sul. All carcasses were necropsied, and endo- and ectoparasites were collected and identified. A total of 82 animals were examined; 87.80% were infected by helminths, 51.21% infested by ectoparasites, and 48.78% were affected by both types of parasites. This study presents the first records of parasitism by Rhipicephalus microplus in Ozotoceros bezoarticus in southern Brazil, and by Ancylostoma caninum in Leopardus geoffroyi worldwide. The study contributes to the knowledge about the parasitic fauna in wild animals of the Pampa biome. The presence of parasites in these threatened species underscores the need for further research into parasitism, which is crucial for their effective management and conservation.

Molecular detection of Rickettsia species in ectoparasites collected from two southern provinces of Cambodia

Arthropod-borne rickettsioses comprise a wide variety of subtypes that are endemic in Cambodia, but there remains very little data on the geographic distribution of the pathogens or their vectors. Surveys were conducted in Koh Kong and Preah Sihanouk Provinces between September 2017 and June 2018 to collect ectoparasites from peridomestic animals and the environment using dragging and flagging methods. Collected ectoparasites were sorted and identified morphologically, then pooled by species, host, and location for molecular detection using Rickettsia genus- and species-specific qPCR and/or multilocus sequence typing (MLST) assays. A total of 14,254 ectoparasites were collected including seven new locality records. Rickettsia species were detected in 35.5% (174/505) of the pools screened representing 3,149 randomly selected ectoparasites from the total collected. Rickettsia asembonensis was detected in 89.6% (147/164) of Rickettsia-positive flea pools and 3.6% (6/164) of the flea pools were positive for both R. asembonensis and Rickettsia felis. Candidatus Rickettsia senegalensis from Ctenocephalides orientis fleas and Rickettsia sp. close to Rickettsia japonica and Rickettsia heilongjiangensis from Haemaphysalis ticks were identified by MLST. This appears to be the first report of these new ectoparasite records and rickettsial species in southern Cambodia, suggesting a potential health risk to military and civilians in this region.

Rickettsia asembonensis Isolated from Four Human Cases with Acute Undifferentiated Febrile Illness in Peru

Rickettsioses, often underreported, pose public health challenges. Rickettsia asembonensis is a potential emerging pathogen that was previously detected in humans, animals, and a variety of arthropods. While its pathogenicity in humans remains unclear, it poses a potential public health threat. Here, we present an extended epidemiological, diagnostic, and genetic analysis of the information provided in a preliminary report on the investigation of rickettsiae in Peru. In particular, we report the detection of R. asembonensis in blood specimens collected from four human patients with an acute undifferentiated fever of a seven- to nine-day duration, all of whom tested negative for other vector-borne pathogens. Additionally, we describe the replicative capacity of the R. asembonensis isolates in cell cultures.

A long-term study on free-ranging jaguar-tick interactions, featuring a novel report of Amblyomma incisum adult infestation

Over nearly 12 years, we collected ticks from free-ranging jaguars (Panthera onca) and performed statistical analyses to comprehend the vector-host relationship throughout the seasons. We evaluated the presence and number of ticks, as well as their association with weight, age, and gender of captured jaguars in the Pantanal and Amazon biomes. Out of 100 captured jaguars (comprising 72 initial captures and 28 recaptures, with 41 females and 31 males), 77 were found to be infested by different tick species. We gathered a total of 1,002 ticks, categorized by the following species in descending order of abundance: Amblyomma sculptum, Amblyomma ovale, Rhipicephalus microplus, Amblyomma triste, Amblyomma cajennense sensu stricto, Amblyomma incisum, and Amblyomma spp. larvae. Apart from weight, statistical analysis indicated that age, gender and seasonality does not significantly affect the presence of different tick species in free ranging jaguars. Notably, A. sculptum adults were more abundant in the first semester, while A. sculptum nymphs and Amblyomma spp. larvae were mainly found during dry months, aligning with their expected life cycle stages. This is the first long-term study in jaguars to correlate seasonality and host factors and also the first time an adult of A. incisum is reported infesting a jaguar.

Fleas (Siphonaptera, Latreille, 1825) from Rio Grande do Sul State, Brazil: Species Diversity, Hosts, and One Health Approach

Background: Fleas are ectoparasitic insects with holometabolous development. It has a hematophagous habit with mouthparts adapted to sting and suck its hosts. There are about 3000 species in the world, ∼61 in Brazil, and 19 in Rio Grande do Sul state. The objective of the research is to catalog the diversity of fleas recorded in the state, their respective hosts, and endosymbionts. Materials and Methods: To this end, a search was carried out in the scientific literature, from articles, books, to abstracts submitted to congresses. Results: The 19 species of fleas occurring in Rio Grande do Sul are divided into 7 families and 10 genera. These ectoparasites, in addition to being found in the environment, were associated with 10 different families of hosts in Rio Grande do Sul, and on the endosymbiont, agents found associated with fleas, there were 7 different species. The main agents researched in the state are Rickettsia spp. and Bartonella spp. The relationships between parasites, hosts, environment, and etiological agents present different scenarios, whether anthropized or conserved, but unknown. Sometimes, this overlap, a factor that aggravates the possibility of spillovers, either from cosmopolitan fleas in these conserved areas, or from their endosymbionts. Conclusion: Thus, it is important to characterize the environment so that the complexities of each location are known for the adoption of environmental and public health policies in each case. The challenges are extensive, but necessary in view of the One Health perspective.

Flea parasitism in wild mammals in the metropolitan region of Sorocaba, São Paulo, Brazil

Fleas are eurixenous ectoparasites that can parasitize different species of warm-blooded animals, including humans, with the possibility of causing irritation and blood spoliation. They are vectors responsible for the transmission of numerous pathogens and have a wide geographical distribution, more frequently in warm regions. Domestic animals (dogs and cats) are preferred hosts, but parasitism can also occur in wild hosts, with a greater variety of parasitic species and strong interaction between these siphonapters and their hosts. During the period from January 2021 to June 2023, flea specimens were collected from wild animals coming from the metropolitan region of Sorocaba, São Paulo. Some of these animals were animals from the zoo's own stock, which were diagnosed with parasitism during routine examinations and others were rescued from the natural environment and sent to the zoo. The flea specimens collected were packed in alcohol 700 GL and sent for microscopic diagnosis. Four groups were diagnosed at the specific level: Ctenocephalides felis, Rhopalopsyllus lutzi, R. lugrubis and Tunga penetrans, and two groups as unidentified species, belonging to the genera Rhopalopsyllus and Polygenis. The parasitized animals were all mammals, belonging to eleven different species, distributed in the Orders Carnivora, Didelphimorphia, Rodentia and Cingulata. Studies on the parasitofauna of wild animals contribute to a greater knowledge about the distribution of parasitic agents and their relationships with the host species.

Epidemiological compatibility of Amblyomma sculptum as possible vector and Panthera onca as reservoir of Cytauxzoon spp. in Midwestern Brazil

Cytauxzoonosis is an acute and highly lethal tick-borne disease of wild and domestic cats, and is widely distributed in Africa, Asia, Europe, the USA and Brazil. So far, only two tick species present on the USA are experimentally confirmed in Cytauxzoon transmission however, in Brazil and other continents, the epidemiology of the disease remains unknown. Evidences points to Panthera onca as a possible reservoir, but there is no evidence to point the vector. Therefore, this study evaluates the presence of Cytauxzoon spp. in wild felids from areas with and without records of Amblyomma sculptum this ixodid for comparison. Overall, 53 blood samples of P. onca, Puma concolor, and Leopardus pardalis from the Midwest region (MR; region with A. sculptum) and 143 blood and/or spleen samples from Leopardus geoffroyi, Leopardus wiedii, Leopardus munoai, Leopardus guttulus, Herpailurus yagouaroundi, L. pardalis, and P. concolor from Rio Grande do Sul State (RS; without A. sculptum). Only one feline sample was negative for Cytauxzoon sp. from MR; no samples from RS were positive. In total, 507 ticks were identified from MR felids, with predominance of A. sculptum (69.23%). In RS, there were 93 ixodids, of which 90.32% were Amblyomma aureolatum. The difference in the tick fauna of the two regions studied (presence/absence of A. sculptum) reflects the results found. This study highlighted A. sculptum as a possible vector since this hemoparasite was abundantly observed in areas where it occurs, also, there was no evidence of Cytauxzoon spp. where it was absent. Additionally, the study supported the suggestion that P. onca is the reservoir for the agent in MR.

Comparative Genomics of the Major Histocompatibility Complex (MHC) of Felids

This review summarizes the current knowledge on the major histocompatibility complex (MHC) of the family Felidae. This family comprises an important domestic species, the cat, as well as a variety of free-living felids, including several endangered species. As such, the Felidae have the potential to be an informative model for studying different aspects of the biological functions of MHC genes, such as their role in disease mechanisms and adaptation to different environments, as well as the importance of genetic diversity for conservation issues in free-ranging or captive populations. Despite this potential, the current knowledge on the MHC in the family as a whole is fragmentary and based mostly on studies of the domestic cat and selected species of big cats. The overall structure of the domestic cat MHC is similar to other mammalian MHCs following the general scheme "centromere-MHC class I-MHC class III-MHC class II" with some differences in the gene contents. An unambiguously defined orthologue of the non-classical class I HLA-E gene has not been identified so far and the class II DQ and DP genes are missing or pseudogenized, respectively. A comparison with available genomes of other felids showed a generally high level of structural and sequence conservation of the MHC region. Very little and fragmentary information on in vitro and/or in vivo biological functions of felid MHC genes is available. So far, no association studies have indicated effects of MHC genetic diversity on a particular disease. No information is available on the role of MHC class I molecules in interactions with Natural Killer (NK) cell receptors or on the putative evolutionary interactions (co-evolution) of the underlying genes. A comparison of complex genomic regions encoding NK cell receptors (the Leukocyte Receptor Complex, LRC and the Natural Killer Cell Complex, NKC) in the available felid genomes showed a higher variability in the NKC compared to the LRC and the MHC regions. Studies of the genetic diversity of domestic cat populations and/or specific breeds have focused mainly on DRB genes. Not surprisingly, higher levels of MHC diversity were observed in stray cats compared to pure breeds, as evaluated by DRB sequencing as well as by MHC-linked microsatellite typing. Immunogenetic analysis in wild felids has only been performed on MHC class I and II loci in tigers, Namibian leopards and cheetahs. This information is important as part of current conservation tasks to assess the adaptive potential of endangered wild species at the human-wildlife interface, which will be essential for preserving biodiversity in a functional ecosystem.

Amblyomma aureolatum Genetic Diversity and Population Dynamics Are Not Related to Spotted Fever Epidemiological Scenarios in Brazil

Regional differences in tick-borne disease epidemiology may be related to biological variations between vector populations. Amblyomma aureolatum (Ixodida: Ixodidae), a neotropical tick, is known from several regions in Brazil. However, only in the metropolitan area of São Paulo (SP) state are there studies that establish its role as a vector of a pathogenic rickettsia (Rickettsia rickettsii). The aim of the study was to analyze the genetic diversity, population dynamics, and rickettsia infection in A. aureolatum populations from different spotted fever scenarios in Brazil. Samples were subjected to DNA extraction, amplification and sequencing of 12S rDNA, cytochrome oxidase subunit II and D-loop mitochondrial markers for tick population analyses, and gltA, htrA, ompA, and ompB genes for rickettsia researches. Of the 7–17 tick haplotypes identified, 5–13 were exclusive to each population and 2–12 for each epidemiological scenario, as well as three haplotypes shared by all populations. Amblyomma aureolatum populations are expanding, and do not appear to be genetically structured vis-a-vis the different epidemiological scenarios studied. Rickettsia bellii (in SP) and Rickettsia felis (in Santa Catarina) were identified as infecting A. aureolatum. No relationship between tick haplotypes and rickettsia types were observed.

Intestinal Parasites of Neotropical Wild Jaguars, Pumas, Ocelots, and Jaguarundis in Colombia: Old Friends Brought Back from Oblivion and New Insights

Neotropical wild felids (NWF) are obligate carnivore species present in Central and South America, and some are considered endangered due to constantly decreasing populations. NWF can become infected by a wide range of protozoan and metazoan parasites, some of them affecting their health conditions and others having anthropozoonotic relevance. Parasitological studies on NWF are still very scarce, and most data originated from dead or captive animals. On this account, the current study aimed to characterize gastrointestinal parasites of free-ranging jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis), and jaguarundis (Herpailurus yagouaroundi), i.e., four out of six NWF species endemic to Colombia. Fecal samples from jaguars (n = 10) and ocelots (n = 4) were collected between 2012 and 2017 as part of the Jaguar Corridor Initiative from six geographic locations in Colombia. In addition, cestode specimens were obtained during puma and jaguarundi necropsies. Scat samples were processed by standardized sodium acetate-acetic acid-formalin (SAF), sedimentation, and flotation techniques and by carbol fuchsin-stained fecal smears. Morphological evaluation of feces showed the presence of one cestode (Spirometra sp.), a nematode (Toxocara cati), an acanthocephalan (Oncicola sp.), and one cyst-forming coccidian (Cystoisospora-like oocysts). Feces oocysts were submitted to a Toxoplasma gondii-specific PCR for species identification, but no product was amplified. The cestodes isolated from a puma and jaguarundi were molecularly characterized by sequencing cytochrome c oxidase subunit I, identifying them as Taenia omissa and as a T. omissa sister lineage, respectively. These results collectively demonstrate the potential role of NWF as natural reservoir hosts for neglected zoonotic parasites (e.g., Spirometra sp., T. cati) and highlight their possible role in parasite transmission to human communities. Due to public health concerns, the occurrence of these parasites should be monitored in the future for appropriate zoonotic management practices in conservation strategies and wild felid health management programs.