Detection of atovaquone-proguanil resistance conferring mutations in Plasmodium falciparum cytochrome b gene in Luanda, Angola

BACKGROUND: The fixed dose combination atovaquone-proguanil is a recently introduced antimalarial for treatment and prophylaxis of Plasmodium falciparum malaria. It is highly effective with a good tolerability profile and a convenient prophylactic regimen. Nevertheless, cases of treatment failure have already been reported, which have been associated to mutations in the cytochrome b gene of the Plasmodium (pfcytb). The presence of atovaquone-proguanil in vivo resistance conferring mutations in pfcytb gene in Luanda, Angola, was investigated, in order to make recommendations on prescribing this antimalarial as prophylaxis for travellers. METHODS: Two hundred and forty nine blood samples from children hospitalized at Luanda Pediatric Hospital for malaria were studied. The PCR-RFLP methodology was used in order to identify pfcytb wild type codon 268 and two point mutations: T802A and A803C. RESULTS: All samples were identified as wild type for pfcytb gene at codon 268. In the studied population, no mutations associated to atovaquone-proguanil treatment failure were found. Prevalence of the studied mutations in the region was estimated to be less than 0.77% (99% significance level). CONCLUSION: Atovaquone-proguanil can be recommended for use by travellers to Luanda with expected high efficacy. This represents an improvement compared to other currently used prophylatic antimalarials in this region. However, it is imperative to continue surveillance

Transforming Growth Factor Beta 2 and Heme Oxygenase 1 Genes Are Risk Factors for the Cerebral Malaria Syndrome in Angolan Children

BACKGROUND: Cerebral malaria (CM) represents a severe outcome of the Plasmodium falciparum infection. Recent genetic studies have correlated human genes with severe malaria susceptibility, but there is little data on genetic variants that increase the risk of developing specific malaria clinical complications. Nevertheless, susceptibility to experimental CM in the mouse has been linked to host genes including Transforming Growth Factor Beta 2 (TGFB2) and Heme oxygenase-1 (HMOX1). Here, we tested whether those genes were governing the risk of progressing to CM in patients with severe malaria syndromes. METHODOLOGY/PRINCIPAL FINDINGS: We report that the clinical outcome of P. falciparum infection in a cohort of Angolan children (n = 430) correlated with nine TGFB2 SNPs that modify the risk of progression to CM as compared to other severe forms of malaria. This genetic effect was explained by two haplotypes harboring the CM-associated SNPs (Pcorrec. = 0.035 and 0.036). In addition, one HMOX1 haplotype composed of five CM-associated SNPs increased the risk of developing the CM syndrome (Pcorrec. = 0.002) and was under-transmitted to children with uncomplicated malaria (P = 0.036). Notably, the HMOX1-associated haplotype conferred increased HMOX1 mRNA expression in peripheral blood cells of CM patients (P = 0.012). CONCLUSIONS/SIGNIFICANCE: These results represent the first report on CM genetic risk factors in Angolan children and suggest the novel hypothesis that genetic variants of the TGFB2 and HMOX1 genes may contribute to confer a specific risk of developing the CM syndrome in patients with severe P. falciparum malaria. This work may provide motivation for future studies aiming to replicate our findings in larger populations and to confirm a role for these genes in determining the clinical course of malaria

Prevalence of pfmdr1, pfcrt, pfdhfr and pfdhps mutations associated with drug resistance, in Luanda, Angola

<p>Abstract</p> <p>Background</p> <p>Malaria is the infectious disease causing the highest morbidity and mortality in Angola and due to widespread chloroquine (CQ) resistance, the country has recently changed its first-line treatment recommendations for uncomplicated malaria, from CQ to artemisinin combination therapies (ACT) in adults, and sulphadoxine/pyrimethamine (S/P) in pregnant women. Loss of SP sensitivity is, however, progressing rapidly in Africa and, in this study, were investigated a number of molecular markers associated to CQ and S/P.</p> <p>Methods</p> <p>Blood samples were collected from 245 children with uncomplicated malaria, admitted at the Pediatric Hospital Dr. David Bernardino (HPDB), Angola, and the occurrence of mutations in <it>Plasmodium falciparum </it>was investigated in the <it>pfmdr1 </it>(N86Y) and <it>pfcrt </it>(K76T) genes, associated with CQ resistance, as well as in <it>pfdhfr </it>(C59R) and <it>pfdhps </it>(K540E), conferring SP resistance.</p> <p>Results</p> <p>The frequencies of <it>pfmdr1 </it>mutations in codon 86 were 28.6% N, 61.3% Y and 10.1% mixed infections (NY). The frequency of <it>pfcrt </it>mutations in codon 76 were 93.9% K, 5.7% T and 0.4% mixed infections (KT). For <it>pfdhfr </it>the results were in codon 59, 60.6% C, 20.6% R and 18.8% mixed infections (CR). Concerning <it>pfdhps</it>, 6.3% of the isolates were bearers of the mutation 540E and 5.4% mixed infections (K540E).</p> <p>Conclusion</p> <p>The results of this epidemiologic study showed high presence of CQ resistance markers while for SP a much lower prevalence was detected for the markers under study.</p

Transforming Growth Factor Beta 2 and Heme Oxygenase 1 Genes Are Risk Factors for the Cerebral Malaria Syndrome in Angolan Children

BACKGROUND: Cerebral malaria (CM) represents a severe outcome of the Plasmodium falciparum infection. Recent genetic studies have correlated human genes with severe malaria susceptibility, but there is little data on genetic variants that increase the risk of developing specific malaria clinical complications. Nevertheless, susceptibility to experimental CM in the mouse has been linked to host genes including Transforming Growth Factor Beta 2 (TGFB2) and Heme oxygenase-1 (HMOX1). Here, we tested whether those genes were governing the risk of progressing to CM in patients with severe malaria syndromes. METHODOLOGY/PRINCIPAL FINDINGS: We report that the clinical outcome of P. falciparum infection in a cohort of Angolan children (n = 430) correlated with nine TGFB2 SNPs that modify the risk of progression to CM as compared to other severe forms of malaria. This genetic effect was explained by two haplotypes harboring the CM-associated SNPs (Pcorrec. = 0.035 and 0.036). In addition, one HMOX1 haplotype composed of five CM-associated SNPs increased the risk of developing the CM syndrome (Pcorrec. = 0.002) and was under-transmitted to children with uncomplicated malaria (P = 0.036). Notably, the HMOX1-associated haplotype conferred increased HMOX1 mRNA expression in peripheral blood cells of CM patients (P = 0.012). CONCLUSIONS/SIGNIFICANCE: These results represent the first report on CM genetic risk factors in Angolan children and suggest the novel hypothesis that genetic variants of the TGFB2 and HMOX1 genes may contribute to confer a specific risk of developing the CM syndrome in patients with severe P. falciparum malaria. This work may provide motivation for future studies aiming to replicate our findings in larger populations and to confirm a role for these genes in determining the clinical course of malaria

Diversity of picornaviruses detected in diarrheal samples from children in Belém, Brazilian Amazon (1982-2019)

Universidade do Estado do Pará. Programa de Pós-graduação em Biologia Parasitária na Amazônia. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Laboratório de Bioinformática. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Laboratório de Vírus Gastroentéricos. Ananindeua, PA, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Programa de Pós-graduação em Medicina Tropical. Rio de Janeiro, RJ, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Laboratório de Enterovírus. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Laboratório de Enterovírus. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Laboratório de Vírus Gastroentéricos. Ananindeua, PA, Brasil.In this investigation, fecal specimens from children with diarrhea were collected from four community studies conducted between 1982 and 2019 in Belém, Brazilian Amazon. A total of 234 samples were tested by quantitative reverse transcription polymerase chain reaction (RT-qPCR) to detect infections by picornaviruses of the Enterovirus (EV), Parechovirus (HPeV), Cosavirus (HCoSV), Kobuvirus (Aichivirus - AiV) and Salivirus (SalV) genera. The positive samples were subjected to different amplification protocols of the VP1 region of the genome, such as nested PCR or snPCR, and were subsequently genotyped by sequencing VP1 and VP3 of the viral genome. Positivity was observed in 76.5% (179/234) of the samples tested using RT-qPCR for at least one virus, and co-infection was observed in 37.4% (67/179) of the cases. EV was detected in 50.8% (119/234), HPeV in 29.9% (70/234), HCoSV in 27.3% (64/234), and AiV/SalV in 2.1% (5/234) of the specimens tested by RT-qPCR. Using nested PCR and/or snPCR techniques, the positivity rates were 94.11% (112/119) for EV, 72.85% (51/70) for HPeV, and 20.31% (13/64) for HCoSV. It was not possible to amplify the samples that were positive for AiV/SalV. Sequencing revealed 67.2% (80/119) EV, 51.4% (36/70) HPeV, and 20.31% (13/64) HCoSV. Forty-five different types of EV were found among species A, B, and C; HCoSV identified five species, including a possible recombinant strain; all HPeV were identified as belonging to species A, in two samples a possible recombination involving three different strains was verified. This study demonstrated the high circulation and diversity of different types of picornaviruses in fecal samples, including those collected more than 30 years ago. This endorsed the evaluation of important points in the epidemiology of these viruses, such as the presence of co-infection and the possibility of knowing more about these agents, considering that some were recently described; therefore, their detection in older samples can provide more data about their ancestry

Enterovirus detection and serotyping of fecal material collected from three children living on the outskirts of Belem city, Amazon region, Brazil, during the first 3 years of life (1983-1986)

Universidade do Estado do Pará. Programa de Pós-graduação em Biologia Parasitária na Amazônia. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Norovírus e outros Vírus Gastroentéricos. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Enterovírus. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Rotavírus. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Enterovírus. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Enterovírus. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Norovírus e outros Vírus Gastroentéricos. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Enterovírus. Ananindeua, PA, Brasil.In the current investigation, fecal material was obtained during a community‐based longitudinal study conducted from 1983 to 1986. This study consisted of 71 children aged newborn to 3 years. A total of 216 samples from three of these children were screened by real‐time quantitative polymerase chain reaction (RT‐qPCR) for the presence of enteroviruses, and positive samples were serotyped by VP1 and VP3 sequencing of the viral genome. Of these, 12 (5.6%) came from symptomatic cases, and the remaining asymptomatic cases were collected fortnightly during the 3 years of study. A positivity of 63.4% (137/216) was obtained by RT‐qPCR, with 58.3% (7/12) in relation to the symptomatic group and 63.7% (130/204) in relation to the asymptomatic group. The 137 positive samples were inoculated into the RD, HEp2C, and L20B cell lines, and the cytopathic effect was observed in 37.2% (51/137) samples. It was also possible to identify 40.9% (56/137), between isolated (n = 46) and nonisolated (n = 10). Enterovirus serotype diversity (n = 25) was identified in this study, with the predominant species being B (80.3%), followed by C (16.1%) and A (3.6%). Cases of reinfection by different serotypes were also observed in the three children studied. Analyses involving different age groups of these minors confirmed that the most affected age was between 12 to 24 months, with a prevalence of 77.6% (52/67). The enterovirus (EV) circulated in the 3 years of research, showed peaks in some months, without defined seasonality. This study demonstrated a high circulation and serotype diversity of EV in fecal samples, collected over 30 years ago. This endorsed the evaluation of important points of the epidemiology of these viruses, such as the presence of coinfection and reinfection of the same individual by different circulating serotypes. Understanding the frequency and duration of EV infections is important in determining their association with persistent diarrhea

Surto de norovírus em um navio cruzeiro ao longo da costa brasileira, março de 2011

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Programa de Pós-Graduação em Virologia. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade do Estado do Pará. Centro de Ciências Biológicas e da Saúde. Programa de Pós-Graduação em Biologia Parasitária na Amazônia. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Vigilância em Saúde do Estado do Pará. Belém, PA, Brasil.Centro de Informações Estratégicas em Vigilância em Saúde. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Outbreaks of gastrointestinal disease may occur on board of cruise ships due to the consumption of contaminated water or food, with a fast person-to-person transmission. Epidemiologic investigations carried out by Centers for Disease Control and Prevention in USA, have confirmed that more than 95% of gastroenteritis outbreaks in cruise ships are caused by norovirus (NoV). In March 2011 an outbreak of acute gastroenteritis (AGE) occurred on a cruise ship with 1,224 passengers and 554 crew members that sailed from Rio de Janeiro, Rio de Janeiro State (Southeast, Brazil) to Manaus, Amazonas State (North) and stopovers in Recife, Pernambuco State, and Fortaleza, Ceará State (Northeast) and Belém, Pará State (North). Epidemiological data were obtained and seven rectal swab samples were collected and tested for NoV detection and characterization by molecular techniques. A total of 53 persons (42 passengers and 11 crew members) developed AGE, 75.5% of whom were older than 60 years old. The symptoms duration was less than 48 h, most of the patients presenting vomiting (79.2%) and diarrhea (73.6%). Most of the cases varied from mild to moderate and only one patient needed parenteral rehydration. Cases of AGE were recorded in eight of 12 vessel floors, especially in the recreational areas. The seven rectal samples collected were all NoV-positive by RT-PCR and all NoV strains were genogrouped as GII by semi-nested PCR. The quantitative real-time PCR produced a 57.1% NoV positivity rate. The partial nucleotide sequencing classified five (71.4%) of these samples as GII.P4. Our findings highlight the need for continuous viral enteropathogens surveillance including cruise ships considering the increase of this kind of touristic option in Brazil.Os surtos da doença gastrointestinal podem ocorrer em navios cruzeiros devido ao consumo de água e comida contaminadas, com rápida transmissão de uma pessoa a outra. Investigações epidemiológicas realizadas pelos Centros de Controle e Prevenção de Doenças, nos EUA, confirmaram que mais de 95% dos surtos de gastroenterite em navios são causados por norovírus (NoV). Em março de 2011, um surto de gastroenterite aguda (GEA) ocorreu em um cruzeiro com 1.224 passageiros e 554 tripulantes que partiu do Rio de Janeiro, Estado do Rio de Janeiro (Sudeste do Brasil) para Manaus, Estado do Amazonas (Norte) com paradas em Recife, Estado do Pernambuco, e Fortaleza, Estado do Ceará (Nordeste) e Belém, Estado do Pará (Norte). Dados epidemiológicos foram obtidos e sete amostras por swab retal foram coletadas e testadas para a detecção e caracterização do NoV por meio de técnicas moleculares. Um total de 53 pessoas (42 passageiros e 11 tripulantes) desenvolveram AGE, dos quais 75,5% eram maiores de 60 anos de idade. Os sintomas duraram menos de 48 h, a maioria dos pacientes apresentou vômito (79,2%) e diarreia (73,6%). A maior parte dos casos obteve variação entre leve e moderado e apenas um paciente necessitou de reidratação parental. Casos de AGE foram registrados em oito dos 12 andares do navio, principalmente nas áreas de recreação. As sete amostras de swab retal coletadas revelaram resultado positivo para NoV por meio de RT-PCR e todas as cepas foram genogrupadas como GII pelo semi-nested PCR. O PCR quantitativo em tempo real produziu uma taxa de positividade de 57,1% para NoV. O sequenciamento parcial de nucleotídeos classificou cinco (71,4%) das sete amostras como GII.P4. Os resultados destacam a necessidade de vigilância contínua dos enteropatógenos virais, incluindo navios cruzeiros, considerando o aumento deste tipo de opção turística no Brasil