Investigation of Leishmania (Viannia) braziliensis Infection in Wild Mammals in Brazil

PURPOSE

Leishmaniasis are infectious and zoonotic diseases and present in cutaneous and visceral forms. Cutaneous leishmaniasis is endemic and widely distributed throughout the state of Espírito Santo, Brazil. Several cases of cutaneous leishmaniasis in humans and dogs associated with Leishmania (Viannia) braziliensis have been reported in the state. This study aimed to investigate the occurrence of natural infection by Leishmania(Viannia) braziliensis in wild mammals found dead (by trampling or natural death) in the Sooretama Biological Reserve, Espírito Santo State.

METHODS

From January 2018 to December 2019, 60 animals were collected. Of these, 47 animals from 12 different species were analyzed. The results were demonstrated using descriptive analysis of the observations to calculate the absolute and relative frequencies of the data.

RESULTS

In the PCR, using specific primers for the genus Leishmania (D1, D2, and D3) and the species Leishmania (Viannia) braziliensis (ISVB/ISVC), 4 positive animals (8.5%) were detected: 1 Cuniculus paca (paca) (25%) and 3 Callithrix geoffroyi (white-faced marmoset) (25%). In the histopathological analysis, the parasitic amastigote form was not observed.

CONCLUSIONS

The natural infection, detected by PCR, by Leishmania (Viannia) braziliensis in Cuniculus paca (paca) and Callithrix geoffroyi (white-faced marmoset) constitutes the first report of infection of this rodent and primate species in the literature. Despite the confirmation of Leishmania (Viannia) braziliensis infection in rodents and primates, the role of these species in the transmission of this zoonosis still needs further observational studies to identify their seasonal variation, transmissibility, infection stability, and the effects of a given parasite on the population and/or individual.

Temperature and exudativory as drivers of the marmoset (Callithrix spp.) daily activity period

Primates are affected by fluctuations in ambient temperatures, mostly through thermoregulatory costs and changes in the availability of food. In the present study, we investigate whether the ambient temperature and proxies of food availability affect the activity period of marmosets (Callithrix spp.). We predicted that: (i) at colder sites, marmosets would spend more time at sleeping sites; (ii) midday resting bouts would be longer at hotter sites; (iii) the onset/cessation of activity and resting behavior at midday would be more closely related to temperature than food availability, and (iv) highly exudativorous groups would have higher total levels of resting. We compiled data on the onset and cessation of activity and the time spent resting at midday from seven marmoset studies from sites with a wide range of temperatures. We used generalized linear mixed models to verify the relationship between the dependent variables (lag between dawn and the onset of activities, lag between cessation of activities and dusk, and proportion of resting during midday) and the minimum and maximum temperatures at the respective study sites, together with proxies of food availability (exudativory rates, the amount of habitat available per individual, and net primary productivity) using each sample month as a sampling unit and the identity of the study as a categorical random factor. At colder sites and during colder months, the marmosets left sleeping trees later in the morning and ceased their activities earlier, while at hotter sites and during hotter months, they spent more time resting during midday. More exudativorous groups become active later in the morning, but also ceased their activities later. The abundance of food did not affect the timing of activities. We provide evidence that both low and high temperatures affect marmosets' activities, and that their activity period appears to be more influenced by the thermal environment than food availability.

Feeding behavior of Geoffroy's marmoset (Callithrix geoffroyi) in an Atlantic forest fragment of South-eastern Brazil

We report on the diet and feeding behaviour of a group of Geoffroy's marmosets (Callithrix geoffroyi) in an Atlantic forest fragment in south-eastern Brazil, studied during the period February 1993 to Januaray 1994. Major food categories were gums (68.6%) fruits (15%), and small animal prey (invertebrates 14.6% and vertebrates 0.8%). Dietary changes were observed between the wet and dry seasons, although they were not statistically significant. Insects and gums were consumed throughout the year but fruits were more prevalent in the diet in the wet season. Plant species exploited for their gums includedInga stipularis, followed byAcacia paniculata, Paulinia carpopodia, andBauhinia angulosa. Chemical analysis of the gum of the four species most used all presented high values for carbohydrates and crude proteins. Fruits of an unidentified species of Myrtaceae (sp. 2) were consumed the most. Animal prey consisted mainly of insects, arachnids, snails, and in three cases, lizards and frogs, with orthopterans being the most prevalent insect prey. This study demonstrates thatC. geoffroyi efficiently exploits resources typically available in secondary and disturbed forest habitat. The main threat to the species is forest destruction, degradation, and fragmentation, but the management of small forest fragments may be an effective corservation strategy.