Molecular screening of Bartonella in free-ranging capybaras (Hydrochoerus hydrochaeris) from Paraná State, Southern Brazil

Bartonella is an emerging group of facultative intracellular bacteria causing circulatory and systemic disorders. Hosts for Bartonella are mostly mammals, specifically rodents, having a growing number of Bartonella species related to their infection. Capybaras (Hydrochoerus hydrochaeris) are abundant native rodents of Brazil, commonly found in urban parks. In the present study, we aimed to perform molecular screening of capybaras for Bartonella spp. Blood samples were collected from 17 free-ranging animals captured in Paraná State, Southern Brazil. None of the collected samples tested positive for the Bartonella-nuoG gene by quantitative polymerase chain reaction (qPCR), although all of them successfully amplified the mammal endogenous glyceraldehyde-3-phosphate dehydrogenase (gapdh) gene. Additionally, all animals were infested exclusively by Amblyomma dubitatum ticks at the time of sampling. This study was part of an active surveillance program, which is critical for monitoring animal health status, particularly in capybaras.

Reproductive Technologies Used in Male Neo-Tropical Hystricomorphic Rodents

This review, which is the first of two, focuses on the male reproductive anatomy and reproductive technologies used in Neo-tropical hystricomorphic rodents with the potential for domestication, which are the agouti (Dasyprocta leporina), the capybara (Hydrochoerus hydrochaeris) and the paca (Cuniculus paca). We consider over seventy references spanning from 1965 to 2020, with the majority of work being done in the past twenty years. Knowledge of the reproductive tract and reproductive technologies is critical to the conservation and preservation of these species. Although all three animals had similarities in their anatomy, such as no overt scrotums and testes located intra-abdominally in the inguinal region, some had unique features—for example, the agouti and the paca had penile spines, and two lateral penile cartilages. High spermatogenic efficiency was noted in the agouti and the paca, making them good candidates for increasing their reproductive performance in conservation programs. A review of the literature has shown that there is increasing work taking place on the reproductive technologies used in these animals; however, a lot of work is still lacking, as, to the author’s knowledge, standard protocols and artificial insemination procedures are yet to be established.

Intranasal oxygen reverses hypoxaemia in immobilised free-ranging capybaras (Hydrochoerus hydrochaeris)

Capybara (Hydrochoerus hydrochaeris) is the main host of tick-borne pathogens causing Brazilian spotted fever; therefore, controlling its population is essential, and this may require chemical restraint. We assessed the impact of chemical restraint protocols on the partial pressure of arterial oxygen (PaO2) and other blood variables in 36 capybaras and the effect of different flows of nasal oxygen (O2) supplementation. The capybaras were hand-injected with dexmedetomidine (5 μg/kg) and midazolam (0.1 mg/kg) and butorphanol (0.2 mg/kg) (DMB, n = 18) or methadone (0.1 mg/kg) (DMM, n = 18). One-third of the animals were maintained in ambient air throughout the procedure, and one-third were administered intranasal 2 L/min O2 after 30 min whereas the other third were administered 5 L/min O2. Arterial blood gases, acid-base status, and electrolytes were assessed 30 and 60 min after drug injection. The DMB and DMM groups did not vary based on any of the evaluated variables. All animals developed hypoxaemia (PaO2 44 [30; 73] mmHg, SaO2 81 [62; 93] %) 30 min before O2 supplementation. Intranasal O2 at 2 L/min improved PaO2 (63 [49; 97] mmHg and SaO2 [92 [85; 98] %), but 9 of 12 capybaras remained hypoxaemic. A higher O2 flow of 5 L/min was efficient in treating hypoxaemia (PaO2 188 [146; 414] mmHg, SaO2 100 [99; 100] %) in all the 12 animals that received it. Both drug protocols induced hypoxaemia, which could be treated with intranasal oxygen supplementation.

Grandes roedores do Abismo Ponta de Flecha (Quaternário), Iporanga, Brasil

O Abismo Ponta de Flecha localizado no Vale do Ribeira é uma gruta vertical complexa que possui grande quantidade de material osteológico, incluindo restos fósseis e recentes de roedores. Como parte do estudo paleontológico e zooarqueológico, o presente trabalho apresenta os fósseis de grandes Caviomorpha desta localidade. Os espécimes são representados por ossos apendiculares de indivíduos jovens e adultos de Cuniculus paca e um dente molar (M1) de um exemplar subadulto de Hydrochoerus hydrochaeris. Não foi possível datar os espécimes, porém ambas são comuns atualmente na região e possuem registro no Pleistoceno. Apesar do Abismo Ponta de Flecha ter sido local de descarte de comunidades indígenas antigas, não há evidências de que estes espécimes foram resultado de caça por humanos ou por outros predadores.

Parasites Circulating in Wild Synanthropic Capybaras (Hydrochoerus hydrochaeris): A One Health Approach

Capybaras (Hydrochoerus hydrochaeris) are affected by a wide range of protozoan and metazoan-derived parasitic diseases. Among parasites of free-ranging capybaras are soil-, water-, food- and gastropod-borne parasitosis, today considered as opportunistic infections in semiaquatic ecosystems. The overlapping of the capybara’s natural ecological habitats with human and domestic animal activities has unfortunately increased in recent decades, thereby enhancing possible cross- or spillover events of zoonotic parasites. Due to this, three synanthropic wild capybara populations in the Orinoco Basin were studied for the occurrence of gastrointestinal parasite infections. A total of forty-six fecal samples were collected from free-ranging capybaras in close proximity to livestock farms. Macroscopical analyses, standard copromicroscopical techniques, coproELISA, PCR, and phylogenetic analysis revealed thirteen parasite taxa. In detail, the study indicates stages of five protozoans, four nematodes, one cestode, and three trematodes. Two zoonotic parasites were identified (i.e., Plagorchis muris, and Neobalantidium coli). The trematode P. muris represents the first report within South America. In addition, this report expands the geographical distribution range of echinocoelosis (Echinocoleus hydrochoeri). Overall, parasitological findings include two new host records (i.e., P. muris, and Entamoeba). The present findings collectively constitute baseline data for future monitoring of wildlife-derived anthropozoonotic parasites and call for future research on the health and the ecological impact of this largest semiaquatic rodent closely linked to humans, domestic and wild animals.

Morphometric Patterns and Blood Biochemistry of Capybaras (Hydrochoerus hydrochaeris) from Human-Modified Landscapes and Natural Landscapes in Brazil

The capybara, Hydrochoerus hydrochaeris, is the largest extant rodent of the world. To better understand the correlation between size and body mass, and biochemical parameters of capybaras from areas with different degrees of anthropization (i.e., different food supplies), we sampled free-ranging capybaras from areas of natural landscapes (NLs) and human-modified landscapes (HMLs) in Brazil. Analyses of biometrical and biochemical parameters of capybaras showed that animals from HMLs were heavier (higher body mass) than those from NL, a condition possibly related to fat deposit rather than body length, as indicated by Body Condition Index (BCI) analyses. Biochemical parameters indicated higher serum levels of albumin, creatine kinase, cholesterol, fructosamine and total protein among capybaras from HMLs than from NLs; however, when all adult capybaras were analyzed together only cholesterol and triglycerides were positively correlated with body mass. We propose that the biochemical profile differences between HMLs and NLs are related to the obesity condition of capybaras among HMLs. Considering that heavier animals might live longer and reproduce more often, our results could have important implications in the population dynamics of capybaras among HMLs, where this rodent species is frequently represented by overgrowth populations that generate several levels of conflicts with human beings.

Análisis multianual de parámetros poblacionales del chigüiro (Hydrochoerus hydrochaeris) en las sabanas inundables colombianas, con miras a su aprovechamiento

El uso sostenible de la vida silvestre requiere información sobre los parámetros demográficos de poblaciones. Si bien, el uso del chigüiro se da en toda su distribución, en Colombia el aprovechamiento legal está suspendido hace dos décadas. Las sabanas inundables de Colombia y Venezuela albergan las mayores poblaciones de chigüiro y se encuentran en riesgo debido a transformaciones antrópicas. Estimamos densidad, tamaño poblacional, estructura de edad y tamaño de grupo de una población de chigüiro. Presentamos información de siete muestreos entre el 2004 y 2017 en una cuadrícula de 3600 ha con transectos espaciados 700 m en Paz de Ariporo, Casanare (Colombia). Se realizaron tres tipos de comparaciones: 1) Períodos climáticos interanuales, iguales en muestras de años contiguos, 2) Períodos climáticos estacionales, diferentes de años contiguos, y 3) por década, períodos climáticos iguales en intervalos de una década. Para todos los muestreos calculamos la tasa de crecimiento poblacional finito (λ) y el índice de producción máxima (Pmax); para los muestreos coincidentes con la cosecha legal en Colombia calculamos el índice de cosecha sostenida (h). En 2005, la población presentó el mayor tamaño (N = 12 802, D = 3,75ind / ha), mientras que en 2017 disminuyó (N = 6 928, D = 2,03ind / ha). En las comparaciones estacionales λ muestra una disminución cercana al 30 %, mientras que, por década, hay fluctuaciones positivas y negativas. Para 2005 y 2015, (h), indica que el aprovechamiento sustentable es viable, sin embargo, es necesario el monitoreo de las poblaciones y su hábitat.