Arthropods Associated with Mammals. Their Importance as Part of the Richness in a Biosphere Reserve in Mexico

Merging socioecological variables to predict risk of Chagas disease

How far are we from predicting the occurrence of zoonotic diseases? In this paper we have made use of both socioecological and ecological variables to predict Chagas disease occurrence. Chagas disease involves, Trypanosoma cruzi, a complex life-cycle parasite which requires two hosts: blood-feeding triatomine insects and vertebrate hosts including humans. We have used a common risk assessment method combined with datasets that imply critical environmental and socioeconomic drivers of Chagas dynamics to predict the occurrence of this disease. We also carried out a network analysis to assess the interactions among triatomines and mammal host species given their human contact via whether hunted, domesticated or associated with anthropogenic landscapes in Mexico. We found that social backwardness variation, lack of health services and altitude had the largest relative influence Chagas events. Triatoma pallidipennis made use of the largest host diversity. Host species shared by the highest number of different triatomines were a woodrat, the highly appreciated bushmeat, and racoon. These results indicate both the predominance of socio-economic factors over ecological ones, and how close we are from predicting zoonotic diseases.

Contribution to the knowledge of Neotrichodectes (Nasuicola) pallidus (Piaget, 1880) (Phthiraptera: Trichodectidae)

The species in the genus Neotrichodectes (Phthiraptera: Ischnocera) infest carnivores. Neotrichodectes (Nasuicola) pallidus (Piaget, 1880), which has been primarily found parasitizing Procyonidae mammals, has been recorded in ring-tailed coatis (Nasua nasua) in the Brazilian states of Minas Gerais, Pernambuco, Santa Catarina, Rio Grande do Sul and Pernambuco. We report a new record of N. pallidus in coatis in the state of Mato Grosso do Sul, central-western Brazil, using morphological (Light and Scanning Electronic Microscopy) and molecular approaches (PCR, sequencing and phylogenetic analysis). Coatis were sampled in two peri-urban areas of Campo Grande city, Mato Grosso do Sul state, Brazil, between March 2018 and March 2019, as well as in November 2021. Lice were collected and examined under light and Scanning Electron Microscopy. DNA was also extracted from nymphs and adults and submitted to PCR assays based on the 18S rRNA and cox-1 genes for molecular characterization. One hundred and one coatis were sampled from 2018 to 2019 and 20 coatis in 2021 [when the intensity of infestation (II) was not accessed]. Twenty-six coatis (26/101-25.7%) were infested with at least one louse, with a total of 59 lice collected in 2018-2019. The II ranged from one to seven lice (mean 2.2 ± SD 1.7). The louse species was confirmed based on the following morphological characteristics: female gonapophyses rounded with the setae along anterior region but not in the medial margin; the male genitalia with a parameral arch not extending beyond the endometrial plate. The same ornamentation was observed on the abdomen of the females, males, and nymphs. The nymphs and the eggs were described in detail for the first time. The obtained 18S rRNA and cox1 sequences from N. pallidus clustered in a clade with other sequences of Ischnocera species. In the present study, a new record of the louse N. pallidus in central-western Brazil was provided, along with new insights into the morphological features of this species, with the first morphology contribution of nymphal and eggs stages.

Acari (Parasitiformes and Acariformes) From Mexico: Analysis of Their Geographical and Host Distribution in Rodentia (Cricetidae)

The study of Acari associated with cricetid rodents in Mexico began at the end of the 1930s. Despite efforts to gathering the information, only listings were built, but none of these studies present an analysis of the available data. A search was made through electronic databases; in addition, some not published records contained at Collection of Laboratorio de Acarología, Facultad de Ciencias, Universidad Nacional Autónoma de México were included in the inventory. Combining the literature records and those deposited in the collection, the total number of species of Acari associated with this family of rodents is 165, distributed in two superorders, four orders, 15 families, and 57 genera. Of the 15 families registered, the richest is Trombiculidae (70 nominal species and 75 taxa), followed by Laelapidae (39 and 42, respectively), Ixodidae (13 nominal and 16 taxa), and Leewenhoekiidae (13 nominal and taxa). From the bibliographic searches, a total of 76 papers were recovered with information on the association between Acari and cricetid rodents in Mexico. The main detected approach in the literature was taxonomic (75 works) and one on detection of pathogens. From the 145 known species of cricetids recorded in Mexico, only 72 (distributed in 18 genera) have been studied and found to host Acari. The use of regionalization of Mexico in provinces allowed us to map the records of Acari associated to cricetids in the most natural approximation of their distribution. We recognize and discuss seven factors that favor the scarcity and asymmetry of acarological studies in Mexico.

Spatial distribution patterns of tick community structure in sympatric jaguars (Panthera onca) and pumas (Puma concolor) from three ecoregions in Mexico

We examined tick communities on wild felid hosts in three ecoregions of Mexico. We collected 186 ticks of 7 species from 10 pumas (Puma concolor) and 9 jaguars (Panthera onca). Tick community composition varied across the ecoregions, and across host species within each region. Overall, Ixodes affinis, Amblyomma ovale, and Amblyomma tenellum were the most abundant species; however, only the latter two ticks were distributed across all three ecoregions, while I. affinis, along with Ixodes spinipalpis, Amblyomma inornatum, and Amblyomma parvum were restricted to more limited geographical regions. Ixodes affinis occurred strictly in southern tropical rainforest ecoregions and was significantly more abundant in Selva Lacandona compared with the Yucatán Peninsula. Amblyomma ovale was significantly more common in the tropical dry forest in the Pacific coastal ecoregion. Amblyomma tenellum abundance tended to be higher on jaguars, while I. affinis abundance was higher on pumas. Regional distribution patterns of some tick species (e.g., I. affinis and I. spinipalpis) may be determined by off-host environmental conditions rather than host factors. In contrast, at the local scale, occurrence and abundance of some tick species (e.g., A. tenellum, A. ovale and Rhipicephalus microplus) might be driven by ecological-host factors, such as habitat use or predator-prey relationships.

Free-living hard ticks (Ixodida: Ixodidae) from three different natural environments of Costa Rica

This paper presents data on free-living ticks collected by flagging and using CO₂ traps in three natural areas in Costa Rica: Carara National Park (CNP), Palo Verde National Park (PVNP), and a Private Forest Reserve in Sarapiquí (SPR). Data were analyzed calculating aspects of alpha diversity (species richness, entropy; dominance index, and evenness); and for beta diversity, compositional similarity between communities of ticks was also calculated. We collected 12,795 ticks belonging to 10 species: Amblyomma coelebs, Amblyomma dissimile, Amblyomma mixtum, Amblyomma naponense, Amblyomma cf. oblongoguttatum, Amblyomma cf. parvum, Amblyomma sabanerae, Amblyomma tapirellum, Haemaphysalis juxtakochi and Ixodes affinis. The number of species and individuals varied between sites: 5970 ticks were collected in CNP, 4443 in PVNP, and 2382 in SPR. Amblyomma cf. oblongoguttatum and A. cf. parvum were collected at all three sites, but A. mixtum was the most abundant species, even though it was not collected in SPR. Values of alpha diversity were calculated for CNP and SPR, while diversity in PVNP was the lowest of the three locations. Evenness was highest in SPR and lowest in CNP. The only community that presented dominance was PVNP. Beta diversity showed low similarity between the three locations with the lowest being CNP and SPR. For the three localities, estimates of the number of tick species based on presence/absence data was higher using flagging than CO₂; and considering the stage of the ticks collected. More larvae were captured using CO₂ traps than by flagging, while flagging was better for collecting adults. To our knowledge this is the first study in Costa Rica that compares these two sampling methods in three different environmental areas.

A Checklist of Macronyssid Species (Mesostigmata: Macronyssidae) From Brazil

Macronyssid mites are parasites of reptiles, birds, and mammals. A checklist of macronyssid species of Brazil is provided, containing 13 genera and 26 species collected from 99 host species.

Ectoparasites of Didelphis virginiana From Yucatan, Mexico

A faunal study is presented to determine the species of ectoparasites found in the opossum Didelphis virginiana (Kerr) (Marsupialia: Didelphidae). For this, Tomahawk traps were placed in the peridomiciles of a rural town in Yucatán, to capture individuals of this marsupial and proceed to the collection of their ectoparasites. A total of 3,023 arthropods were collected from 145 opossums. The most frequent ectoparasites were the acarines Ornithodoros (Alectorobius) nr. talaje (64.8%) (Argasidae); Ornithonyssus wernecki Fonseca (53.8%) (Macronyssidae) and Didelphilicus serrifer Fain (25.5%) (Atopomelidae); the ticks Amblyomma parvum Aragão (8.3%) and A. mixtum Koch (10.3%) (Ixodidae); and the fleas Ctenocephalides felis (Bouché) (20.7%) and Pulex simulans Baker (8.3%) (Pulicidae). It is concluded that the ectoparasite fauna of this marsupial is mainly composed of euryxenous organisms, which have been documented as vectors of diseases caused by rickettsial bacteria. Since D. virginiana is widely adapted to the peridomiciliary environment in the region, this study allows recognizing those that represent a potential risk for the transmission of vector-borne zoonotic diseases.