Banca de DEFESA: GABRIELA MERCEDES ULLOA URIZAR

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : GABRIELA MERCEDES ULLOA URIZAR
DATE: 30/08/2023
TIME: 08:00
LOCAL: Sala virtual
TITLE:

MOLECULAR EPIDEMIOLOGY OF PLASMODIUM SPP. AT THE HUMAN-WILDLIFE INTERFACE IN THE PERUVIAN AMAZON

KEY WORDS:

Zoonosis, malaria, Plasmodium, anthropozoonosis, reservoirs, indigenous population, Amazonia, One Health

PAGES: 160
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Malaria remains one of the most important infectious diseases for public health. Global efforts to reduce malaria have reduced the global incidence of cases from 8.2% in 2000 to 5.9% in 2021. However, the parasite species involved in zoonotic malaria are becoming increasingly important. Currently, Plasmodium knowlesi, a zoonotic parasite, causes high malaria prevalence in South-East Asia. Natural human infections with two endemic zoonotic species, Plasmodium brasilianum (morphologically, genetically and immunologically indistinguishable from Plasmodium malariae) and Plasmodium simium (almost indistinguishable from Plasmodium vivax), have been reported in South America. In the Amazon, rural, riverine and indigenous populations often live in geographical areas where malaria is endemic and where there is a high biodiversity of wildlife. This ecological link, in the presence of competent vectors, favors the existence of possible scenarios of anthropozoonotic transmission of malaria, becoming silent foci that threaten malaria control. Therefore, the aim of this study was to determine the epidemiology of parasite species associated with zoonotic malaria and their possible adaptive radiation to non-human vertebrate hosts at the human-wildlife interface in the Peruvian Amazon. METHODOLOGY: Between 2007 and 2020, a molecular epidemiological study was conducted in the Yagua indigenous community of Nueva Esperanza, located on the border between Peru and Brazil, comprising a cross-sectional analysis of individuals from the local community and a retrospective analysis of wildlife. In February 2020, whole blood samples were collected from 141 villagers and, over a period of 11 years (2007 - 2015 and 2019 - 2020), filter paper blood samples were collected from 1053 wildlife individuals (343 non-human primates -NHPs-, 341 large rodents, 250 ungulates, 71 edentates and 48 carnivores) from subsistence hunting by the local population. Nested PCR (nPCR) targeting the cox3 gene and real-time PCR (qPCR) targeting the 18S rRNA gene were used to identify malaria parasite species. To determine the diversity of Plasmodium parasites in human vertebrate and wildlife hosts, nPCR targeting the mitochondrial cytb gene was used. Finally, phylogenetic analysis was performed using molecular sequences of positive samples. RESULTS: The overall prevalence of Plasmodium spp. was 51.9%, 178/343 in NHPs; 43.3%, 61/141 in humans; 20.8%, 52/250 in ungulates; 12.5%, 6/48 in carnivores; 10.3%, 35/216 in larger rodents and 0.0%, 0/71 in edentates. Regarding the malaria parasites, P. vivax/simium was identified as the most common species in humans (36.2%, 51/141), NHPs (14.9%, 51/343) and larger rodents (1.5%, 5/341), and P. brasilianum/malariae in NHPs (19.01%, 65/342) and humans (4.3%, 6/141). Humans and NHPs share identical malaria parasite lineages, including P. falciparum specie (1.5%, 2/141 in humans and 0.3%, 1/343 in NHPs. In addition, five new Plasmodium lineages were identified, one of which was zoonotic, called Plasmodium spp. Type I, found in ungulates (9.6%, 24/250), NHPs (5.3%, 18/343), humans (5.0%, 7/141), larger rodents (4.1%, 14/341), domestic rodents (2.2%, 1/45) and carnivores (2.1%, 1/48). Two of the lineages were found in wild animals but not in humans; Plasmodium spp. type II was identified in NHPs (5.0%, 17/343), carnivores (2.1%, 1/48) and ungulates (1.2%, 3/250) and Plasmodium spp. type III in carnivores (2.1%, 1/48), ungulates (0.8%, 2/250), larger rodents (0.6%, 2/216) and NHPs (0.3%, 1/343). The last two lineages were found only in ungulates of Mazama americana specie: Plasmodium spp. type IV (2.0%, 5/250) and type V (0.8%, 2/250). Only 6.0% (3/50) of the malaria-positive villagers reported fever. Based on the correlation between parasitaemia and qPCR cycle thresholds (CTs), P. vivax/simium parasitaemia was found to be very low in humans (CT 31.2 ± 4.7) and almost undetectable in NHPs. In addition, malaria parasitaemia in NHPs is significantly lower (Ct 32.9 ± 3.1) than in humans. CONCLUSION: Phylogenetic analysis of malaria species between humans and NHPs suggests the presence of naturally acquired anthropozoonotic infections in local human populations. The new lineage, Plasmodium spp. Type I, present in humans and wildlife forms a monophyletic clade that shares a common ancestor with known human malaria lineages, but represents a sister clade to P. falciparum. The high prevalence of asymptomatic and low parasitaemia in humans indicates acquired immunity due to the mode of infection caused by P. vivax specie. Similarly, very low and almost undetectable parasitaemia in wild NHPs is evidence of their capacity as reservoirs for malaria. The human-wildlife interface represents a natural reservoir of malaria parasites and effective interspecies transmission, the impact of which on disease needs to be assessed and monitored.

BANKING MEMBERS:
Externa à Instituição - ALESSANDRA NAVA
Externo à Instituição - ALESSANDRA SCOFIELD AMARAL
Externo ao Programa - 1111612 - JOSÉ LEDAMIR SINDEAUX NETO
Interna - 2308115 - MICHELE VELASCO OLIVEIRA DA SILVA
Interno - 742.439.501-72 - PEDRO GINÉS MAYOR APARICIO - UNIBARCELONA
Interno - 388501 - WASHINGTON LUIZ ASSUNCAO PEREIRA