Mitochondrial DNA reveals species composition and phylogenetic relationships of hookworms in northeastern Brazil.

Hookworm infection persists focally in rural communities in Brazil. In this study, we analyze the mitochondrial nucleotide sequences obtained from hookworms infecting humans in order to characterize species composition and assess their genetic diversity and phylogenetic relationships. Field expeditions and cross-sectional surveys were carried out in three Brazilian municipalities from 2013 to 2017: Nossa Senhora de Nazaré (n = 605) and Teresina (n = 297), in the state of Piauí, and Russas (n = 213) in the State of Ceará. Parasitological methods were used to evaluate fecal samples. Hookworm-positive samples had a partial mtDNA cox1 amplified and sequenced. Maximum-likelihood and Bayesian analysis demonstrated two strongly-supported clades, including Group A, corresponding to Necator americanus, and Groups B and C, corresponding to Necator sp. Group A was divided into three main clusters: A1 grouped with Asian sequences, A2 grouped with African sequences, and A3 had only Asian sequences. Group B was closely related to Necator sp., showing a sequence similarity of 98%-99% with African samples circulating zoonotically among humans and non-human primates. Twenty three N. americanus haplotypes were identified. N. americanus Median-Joining network revealed three distinct groups, designated again as A1, A2, and A3. Group A1 presented a star-like shape, with one dominant haplotype. The molecular dating suggested that the two clades dividing N. americanus and Necator sp. began to diverge during the middle Pleistocene. The most recent common ancestor among N. americanus groups was dated to the late Pleistocene. Hookworms circulating in the studied communities are structured in well-defined subpopulations presenting both Asian and African genetic backgrounds. This reveals a double origin for hookworms in northeastern Brazil and opens up new possibilities in phylogeographic, evolutionary, and molecular epidemiological studies in regions where hookworms persists focally, despite control efforts. The presence of potentially zoonotic species and the specific identification of Necator sp. should be further investigated.

Focal persistence of soil-transmitted helminthiases in impoverished areas in the State of Piaui, Northeastern Brazil.

This study aims to describe the prevalence, distribution, and factors associated with soil-transmitted helminthiases (STHs) in rural localities in Piaui, Brazil. Two cross-sectional surveys (n=605 subjects; 172 families) were carried out in order to obtain socio-demographic, anthropometric, spatial and parasitological data. Parasites were evaluated using Kato-Katz and centrifugal sedimentation techniques. Eggs were measured to assess infection with zoonotic Strongylida parasites. Kernel maps were constructed with Q-GIS. The prevalence of hookworm infection was 12.4% (75/605). Other helminthes found were Trichuris trichiura (n=1; 0.2%) and Hymenolepis nana (n=1; 0.2%). The hookworm positivity rate was significantly lower among subjects who had used albendazole when compared with individuals who had not used anthelmintics or had used antiprotozoal drugs in the last 6 months (8/134 [6.0%] vs. 59/415 [14.2%]; p=0.009). A total of 39/172 (22.7%) families had at least one infected member. The association between the number of dwellers and hookworm positivity in the family was present in a logistic regression multivariate model. Assessment of worm burdens showed 92.2% light, 6.2% moderate, and 1.6% heavy infections. Hookworm eggs (n=34) measured 57.2 - 75.4 µm in length and 36.4 - 44.2 µm in width (mean ± SD = 65.86 ± 4.66 µm L and 40.05 ± 1.99 µm W), commensurate with human hookworms. Hotspots suggest that transmission has a focal pattern. STHs persist in impoverished rural areas in Northeastern Brazil where currently available control strategies (mass drug administration) apparently do not allow the elimination of the infection.

Genetic diversity of Giardia duodenalis circulating in three Brazilian biomes.

Giardia duodenalis has a wide genetic variety, and its characterization helps in the understanding of its transmission dynamics and in the development control strategies. This study aimed to assess the genetic diversity of G. duodenalis obtained in different Brazilian biomes and estimate their phylogenetic relationships. Three surveys including 944 participants were carried out in the municipalities of Russas (RSS, Caatinga semiarid biome), Santa Isabel do Rio Negro (SIRN, Amazon rainforest biome) and Nossa Senhora de Nazaré (NSN, Cerrado-Caatinga transition biome). G. duodenalis-positive fecal samples were submitted to amplification of gene fragments encoding ß-giardin (ßG, N = 71), glutamate dehydrogenase (GDH, N = 42), and triosephosphate isomerase (TPI, N = 27). Overall detection rates of assemblage A in G. duodenalis-positive samples through ßG, GDH and TPI were 22/71 (31%), 13/42 (31%), and 13/27 (48.1%), respectively. Concerning assemblage B, rates with distinct genetic markers were 49/71 (69%), 29/42 (69%), and 14/27 (51.9%), respectively. In the Amazon, assemblage B was more prevalent (77.8%, 71.8% and 65% through ßG, GDH and TPI, respectively), while in the Cerrado biome assemblage A predominated (50%, 66.6%, and 85.7%, through ßG, GDH and TPI, respectively). In Caatinga biome assemblage A also predominated (71.4%, through ßG). Thirty new sub-assemblages are described for assemblage B (24 ßG and six TPI), as well as three new sub-assemblages are described for assemblage A (one GDH and 2 TPI). Higher genetic diversity of assemblage B in the Amazon may be related to demographic concentration leading to a more complex transmission network within a poorer sanitation background. The high genetic divergence between assemblages A and B (5.5-6.3%) support the proposal of taxon separation in distinct species.

Frequency and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, and Entamoeba hartmanni in the context of water scarcity in northeastern Brazil.

This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects) to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR). The overall prevalence of infection was 22/213 (10.3%). The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.

Frequency and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, and Entamoeba hartmanni in the context of water scarcity in northeastern Brazil

This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects) to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR). The overall prevalence of infection was 22/213 (10.3%). The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.

Parasitological and immunological diagnoses from feces of captive-bred snakes at Vital Brazil Institute.

Fecal samples from 56 snakes at the Vital Brazil Institute, in the city of Niterói, Rio de Janeiro, were tested using the sedimentation and flotation techniques to investigate the evolutionary forms of parasites such as helminths and protozoa, and using enzyme immunoassay techniques to detect antigens of Cryptosporidium sp. and Giardia sp. Among the animals tested, 80.3% were positive for parasites. Out of these, there were 16 Bothrops jararaca, 16 B. jararacussu and 13 Crotalus durissus. The prevalence of parasitic nematodes was 41.1%, and nematodes were found in all three snake species. Among these, the most frequent finding was eggs of Kalicephalus sp., which were diagnosed in 25% of the snakes. The positivity for protozoa detected using parasite concentration techniques was 75%, including oocysts of Caryospora sp. in 75%, cysts with morphology similar to Giardia sp. 3.6%, amoeboid cysts in 41.1% and unsporulated coccidia oocysts in 8.9%. Immunoassays for Cryptosporidium sp. antigens produced positive findings in 60.7%. Pseudoparasites were detected in 64.3%. These results show that there is a need to improve the sanitary handling of captive-bred snakes, and also for the animal house that supplies rodents to feed them. The results also highlight that diagnostic tests should be performed periodically on stool specimens from captive-bred snakes.

Parasitological and immunological diagnoses from feces of captive-bred snakes at Vital Brazil Institute / Diagnóstico parasitológico e imunológico em fezes de serpentes cativas do Instituto Vital Brazil

Fecal samples from 56 snakes at the Vital Brazil Institute, in the city of Niterói, Rio de Janeiro, were tested using the sedimentation and flotation techniques to investigate the evolutionary forms of parasites such as helminths and protozoa, and using enzyme immunoassay techniques to detect antigens of Cryptosporidium sp. and Giardia sp. Among the animals tested, 80.3% were positive for parasites. Out of these, there were 16 Bothrops jararaca, 16 B. jararacussu and 13 Crotalus durissus. The prevalence of parasitic nematodes was 41.1%, and nematodes were found in all three snake species. Among these, the most frequent finding was eggs of Kalicephalus sp., which were diagnosed in 25% of the snakes. The positivity for protozoa detected using parasite concentration techniques was 75%, including oocysts of Caryospora sp. in 75%, cysts with morphology similar to Giardia sp. 3.6%, amoeboid cysts in 41.1% and unsporulated coccidia oocysts in 8.9%. Immunoassays for Cryptosporidium sp. antigens produced positive findings in 60.7%. Pseudoparasites were detected in 64.3%. These results show that there is a need to improve the sanitary handling of captive-bred snakes, and also for the animal house that supplies rodents to feed them. The results also highlight that diagnostic tests should be performed periodically on stool specimens from captive-bred snakes.

Foram analisadas amostras fecais de 56 serpentes do Instituto Vital Brazil, Niterói, Rio de Janeiro, por técnicas de sedimentação e flutuação, para pesquisa de formas evolutivas de parasitos como helmintos e protozoários, e imunoenzimáticas para detecção de antígenos de Cryptosporidium sp. e Giardia sp. Dos animais estudados, 80,3% foram positivos para parasitos, dos quais 16 pertenciam à espécie Bothrops jararaca, 16 à B. jararacussu e 13 à Crotalus durissus. A prevalência de nematódeos parasitos foi de 41,1%, sendo evidenciados nas três espécies de serpentes. Dentre estes, o mais frequente foi o encontro de ovos de Kalicephalus sp., diagnosticado em 25% das serpentes. A positividade para protozoários detectados pelas técnicas de concentração foi de 75%, nas quais oocistos de Caryospora sp. foram detectados em 75%, cistos com morfologia similar a Giardia sp. em 3,6%, cistos de amebídeos em 41,1% e oocistos não esporulados de coccídios em 8,9%. Obteve-se positividade para antígenos de Cryptosporidium sp. por imunoensaio em 60,7%. Pseudoparasitos foram detectados em 64,3%. Estes resultados apontam para a necessidade de aprimoramento do manejo sanitário das serpentes cativas, bem como no biotério que fornece roedores para sua alimentação, destacando a realização periódica de diagnóstico nas amostras fecais de serpentes cativas.