Serological survey and DNA screening of Leptospira spp. in free-living adult tufted capuchin monkeys (Cebus apella nigritus) in a forest reserve Southeast São Paulo State, Brazil

Influence of landscape structure on previous exposure to Leptospira spp. and Brucella abortus in free-living neotropical primates from southern Brazil

The environments in which neotropical primates live have been undergoing an intense fragmentation process, constituting a major threat to the species' survival and causing resource scarcity, social isolation, and difficulty in dispersal, leaving populations increasingly vulnerable. Moreover, the proximity of wild environments to anthropized landscapes can change the dynamics of pathogens and the parasite-host-environment relationship, creating conditions that favor exposure to different pathogens. To investigate the previous exposure of free-living primates in Rio Grande do Sul State (RS), southern Brazil, to the bacterial agents Leptospira spp. and Brucella abortus, we investigated agglutinating antibodies against 23 serovars of Leptospira spp. using the microscopic agglutination test and B. abortus acidified antigen test in primate serum samples; 101 samples from primates captured between 2002 and 2016 in different forest fragments were used: 63 Alouatta caraya, 36 Alouatta guariba clamitans, and 02 Sapajus nigritus cucullatus. In addition, the forest remnants where the primates were sampled were characterized in a multiscale approach in radii ranging from 200 to 1400 m to investigate the potential relationship of previous exposure to the agent with the elements that make up the landscape structure. The serological investigation indicated the presence of antibodies for at least one of the 23 serovars of Leptospira spp. in 36.6% (37/101) of the samples analyzed, with titers ranging from 100 to 1600. The most observed serovars were Panama (17.8%), Ballum (5.9%), Butembo (5.9%), Canicola (5.9%), Hardjo (4.9%), and Tarassovi (3.9%); no samples were seropositive for Brucella abortus. Decreased forest cover and edge density were the landscape factors that had a significant relationship with Leptospira spp. exposure, indicating that habitat fragmentation may influence contact with the pathogen. The data generated in this study demonstrate the importance of understanding how changes in landscape structure affect exposure to pathogenic microorganisms of zoonotic relevance. Hence, improving epidemiological research and understanding primates' ecological role in these settings can help improve environmental surveillance and conservation strategies for primate populations in different landscapes.

Leptospira Seroprevalence in Free-Ranging Long-Tailed Macaques (Macaca fascicularis) at Kosumpee Forest Park, Maha Sarakham, Thailand

BACKGROUND

Leptospirosis is a zoonotic disease that is ubiquitously distributed and is classified as a re-emerging infectious disease in humans and animals. Many serovars are carried by wildlife; all of them are capable of causing illness in humans. The purpose of this study was to investigate the prevalence of Leptospirosis in wild long-tailed macaques (Macaca fascicularis) at Kosumpee Forest Park, Mahasarakham, Thailand.

METHODS

A cross-sectional study was conducted at the park. Blood samples were collected via saphenous vein from 30 free-ranging long-tailed macaques. All samples were tested by the microscopic agglutination test. The LipL32 gene was used to detect pathogenic Leptospira in blood samples by conventional polymerase chain reaction.

RESULTS

Screening of the 30 wild macaques showed an overall Leptospira seroreactivity of 13.33%. Three of 30 macaques reacted against Leptospira serovar Shermani and one macaque was infected with Leptospira serovar Sejroe. None of the macaques presented clinical signs of leptospirosis. None of the blood samples showed the detection of the LipL32 gene.

CONCLUSIONS

The results indicate that the long-tailed macaques at Kosumpee Forest Park may act as natural reservoirs for Leptospirosis. Further, the results provide evidence-based information indicating that several pathogenic Leptospira serovars are circulating in the wild macaques in the study area.

First detection of antibodies against Leptospira among free-ranging neotropical non-human primates in the Peruvian Amazon lowland rainforest

Leptospirosis is a bacterial zoonotic disease with multiple serogroups that infects wildlife and humans alike. Several studies have detected the presence of leptospiral antibodies in captive Neotropical primates, suggesting that they are asymptomatic carriers. However, the presence of antibodies in free-ranging primates and their potential role as reservoirs for this pathogen is not known. In this study, we used the Microscopic Agglutination Test (MAT) to screen two species of free-ranging tamarins for the presence of Leptospira antibodies using a panel of 21 serogroups. A total of 56 primates (26 Leontocebus weddelli and 30 Saguinus imperator) were screened at the Estación Biológica Río Los Amigos in Madre de Dios, Peru. MAT results with titres of ≥100 in single samples were considered seropositive. Prevalence ratios (PR) were estimated for age group, sex and host species identity. Overall, 51.8% (29/56) of animals were reactive for at least one Leptospira serogroup. Serogroups were distributed as follows: Iquitos (41.1%), Icterohaemorrhagiae (14.3%), Sejroe (3.6%), Autumnalis (1.8%) and Bataviae (1.8%). No significant differences (p > .05) were found for seropositivity frequencies among categories within assessed variables. These results suggest that free-ranging L. weddelli and S. imperator might serve as reservoirs for pathogenic Leptospira serogroups. Given increasing human-wildlife contact, future studies that test for active infection are required to determine potential transmission risks to humans.