The 2021 re-emergence of yellow fever in non-human primates in the state of Rio Grande do Sul (RS), southernmost Brazil, resulted in the death of many howler monkeys (genus Alouatta) and led the state to declare a Public Health Emergency of State Importance, despite no human cases reported. In this study, near-complete genomes of yellow fever virus (YFV) recovered from the outbreak were sequenced and examined aiming at a better understanding of the phylogenetic relationships and the spatio-temporal dynamics of the virus distribution. Our results suggest that the most likely sequence of events involved the reintroduction of YFV from the state of São Paulo to RS through the states of Paraná and Santa Catarina, by the end of 2020. These findings reinforce the role of genomic surveillance in determining the pathways of distribution of the virus and in providing references for the implementation of preventive measures for populations in high risk areas.

Two-hundred-nine free ranging non-human primates from 31 locations throughout Costa Rica were captured and released between 1993 and 2012, and blood samples, sera or plasma were collected, to detect antigens and antibodies, and so assess the distribution of active and passive flavivirus infections over time. A competitive enzyme-linked immunoassay for the detection of antibodies was used to determine the distribution of past flavivirus infections over time, while Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) was used to detect active West Nile Virus (WNV) and Dengue virus (DENV) infections. The first serological evidence of flavivirus in these animals was determined in 1993, at the same time when DENV re-emerged in humans from Costa Rica. An increase in the number of seropositive wild monkeys to flavivirus was determined over time in the country (11.3% seropositivity in 1993–1996, 20.7% in 2001–2008, and finally 52.9% in 2010–2012). Furthermore, the presence of DENV2 was detected in samples from four howler monkeys collected in 2001–2002, whereas DENV2, DENV3, and DENV4 were found in samples from four white-faced monkeys, and WNV in three howler monkeys living in the Pacific coast of Costa Rica during 2010–2012. The habitat where the positive PCR individuals lived were characterized as fragmented forests, having temperatures ranging from 26°C to 28°C, altitudes below 250 meters above sea level, high precipitation during 7 to 9 months (1500–4000 mm), and a marked dry season of 3 to 5 months. All these animals were living near mangroves; however, they did not show clinical signs of illness at the time of sampling. Results obtained show that the number of seropositive wild non-human primates to flavivirus were increasing during time in the country, longitudinal studies are needed to investigate their role as sentinels of these viruses and to determine if flavivirus infections can affect these species.

We describe the hematology and serum biochemistry values for 26 free-ranging Panamanian white-faced capuchins (Cebus imitator) in Costa Rica. Howell-Jolly bodies and microfilariae were obs...

Chikungunya virus (CHIKV) is primarily associated with non-human-primates (NHPs) in Africa, which also infect humans. Since its introduction to Brazil in 2014, CHIKV has predominantly thrived in urban cycles, involving Aedes aegypti mosquitoes. Limited knowledge exists regarding CHIKV occurrence and implications in rural and sylvatic cycles where neotropical NHPs are potential hosts, from which we highlight Leontopithecus chrysomelas (Kuhl, 1820), the golden-headed lion tamarin (GHLT), an endangered species endemic to the Atlantic Forest (AF) in Southern Bahia State, Brazil. The present study investigated wild GHLT groups across two municipalities, Ilhéus and Una, Bahia. Surveys were conducted in three groups within cocoa agroforests (cabrucas) in Ilhéus, and four groups in anthropized forest and agroforestry fragments in Una, between 2021 and 2022. Thirty-two GHLT specimens were captured and chemically immobilized, examined and submitted to blood sample collection; nine specimens were later recaptured in 2022, totaling 41 samples. CHIKV viremia was not detected in any specimens (as assayed by RT-qPCR). Plaque reduction neutralization test (PRNT₉₀) detected CHIKV antibodies in two (6.3%) GHLTs, with 10–20 antibody titers. Seroprevalence in 2021 was 5.6% and in 2022 was 8.7% with an incidence of 4.5%, whereas, a male adult tested seropositive in both years, suggesting either natural re-exposure and antibody maintenance over time. All samples tested seronegative for Mayaro Virus. Eight mosquito species from the Culicidae family were collected, identified and assayed for CHIKV genomes, showing negative results. This study provides the first evidence of natural CHIKV exposure among free-living GHLTs in Brazil, emphasizing their susceptibility and potential role as reservoirs. These findings underscore the possible consequences of anthropic disturbances in the Brazilian AF, without a seroprevalence difference between non-protected forest formations, agroforest fragments and various mosaic farming landscapes in South Bahia, and highlight the importance of conservation efforts for this endemic and endangered primate species.

In Brazil, Plasmodium infections in non-human primates (NHPs) have been associated with P. simium and P. brasilianum, which are morphologically and genetically similar to the human-infecting species P. vivax and P. malariae, respectively. Surveillance and monitoring of wild NHPs are crucial for understanding the distribution of these parasites and assessing the risk of zoonotic transmission. This study aimed to detect the presence of Plasmodium spp. genetic material in Platyrrhini primates from 47 municipalities in the states of Bahia and Minas Gerais. The animals were captured using Tomahawk-type live traps baited with fruit or immobilized with tranquilizer darts. Free-ranging individuals were chemically restrained via inhalation anesthesia using VetBag^® or intramuscular anesthesia injection. Blood samples were collected from the femoral vein. A total of 298 blood and tissue samples were collected from 10 primate species across five genera: Alouatta caraya (25), Alouatta guariba clamitans (1), Callicebus melanochir (1), Callithrix geoffroyi (28), Callithrix jacchus (4), Callithrix kuhlii (31), Callithrix penicillata (175), Callithrix spp. hybrids (15), Leontopithecus chrysomelas (16), Sapajus robustus (1), and Sapajus xanthosthernos (1). Molecular diagnosis was performed using a nested PCR targeting the 18S small subunit ribosomal RNA (18S SSU rRNA) gene, followed by sequencing. Of the 298 samples analyzed, only one (0.3%) from Bahia tested positive for Plasmodium brasilianum/P. malariae. This represents the first detection of this parasite in a free-living C. geoffroyi in Brazil. These findings highlight the importance of continued surveillance of Plasmodium infections in NHPs to identify regions at risk for zoonotic transmission.