Serological detection of West Nile virus in horses and chicken from Pantanal, Brazil

In an effort to detect West Nile virus (WNV) in Brazil, we sampled serum from horses and chickens from the Pantanal region of the state of Mato Grosso and tested for flavivirus-reactive antibodies by blocking ELISA. The positive samples were further confirmed for serological evidence of WNV infection in three (8%) of the 38 horses and one (3.2%) of the 31 chickens using an 80% plaque-reduction neutralisation test (PRNT80). These results provide evidence of the circulation of WNV in chickens and horses in Pantanal.

Climatic factors influencing triatomine occurrence in Central-West Brazil

We estimated the geographic distributions of triatomine species in Central-West Region of Brazil (CW) and analysed the climatic factors influencing their occurrence. A total of 3,396 records of 27 triatomine species were analysed. Using the maximum entropy method, ecological niche models were produced for eight species occurring in at least 20 municipalities based on 13 climatic variables and elevation. Triatoma sordida and Rhodnius neglectus were the species with the broadest geographic distributions in CW Brazil. The Cerrado areas in the state of Goiás were found to be more suitable for the occurrence of synanthropic triatomines than the Amazon forest areas in the northern part of the state of Mato Grosso. The variable that best explains the evaluated models is temperature seasonality. The results indicate that almost the entire region presents climatic conditions that are appropriate for at least one triatomine species. Therefore, it is recommended that entomological surveillance be reinforced in CW Brazil.

Occult hepatitis B virus infection among injecting drug users in the Central-West Region of Brazil

The prevalence of occult hepatitis B virus (HBV) infection was investigated in 149 hepatitis B surface antigen (HBsAg) negative injecting drug users (IDUs) in the Central-West Region of Brazil. Of these individuals, 19 were positive for HBV DNA, resulting in an occult HBV infection prevalence of 12.7% (19/149); six of these 19 individuals had anti-HBV core and/or anti-HBV surface antibodies and 13 were negative for HBV markers. All IDUs with occult hepatitis B reported sexual and/or parenteral risk behaviours. All HBV DNA-positive samples were successfully genotyped. Genotype D was the most common (17/19), followed by genotype A (2/19). These findings reveal a high prevalence of occult HBV infection and the predominance of genotype D among IDUs in Brazil's Central-West Region.

Prevalence of hepatitis C virus infection among recyclable waste collectors in Central-West Brazil

The prevalence of hepatitis C virus (HCV) in a population of recyclable waste collectors (n = 431) was assessed using a cross-sectional survey in all 15 cooperatives in the city of Goiânia, Central-West Brazil. The HCV prevalence was 1.6% (95% confidence interval: 0.6-3.6) and a history of sexually transmitted infections was independently associated with this infection. HCV RNA (corresponding to genotype 1; subtypes 1a and 1b) was detected in five/seven anti-HCV-positive samples. Although the study population reported a high rate (47.3%) of sharps and needle accidents, HCV infection was not more frequent in recyclable waste collectors than in the general Brazilian population.

Serologic survey of West Nile virus in horses from Central-West, Northeast and Southeast Brazil

Since the emergence of West Nile virus (WNV) in North America in 1999, there have been several reports of WNV activity in Central and South American countries. To detect WNV in Brazil, we performed a serological survey of horses from different regions of Brazil using recombinant peptides from domain III of WNV. Positive samples were validated with the neutralisation test. Our results showed that of 79 ELISA-positive horses, nine expressed WNV-specific neutralising antibodies. Eight of the infected horses were from the state of Mato Grosso do Sul and one was from the state of Paraíba. Our results provide additional evidence for the emergence of WNV in Brazil and for its circulation in multiple regions of the country.

Prevalence and genetic characterisation of HTLV-1 and 2 dual infections in patients with pulmonary tuberculosis in Central-West Brazil

Human T-cell lymphotropic virus (HTLV) may impact the clinical course of tuberculosis (TB). Both infections are highly endemic in Brazil. The aim of this study was to assess the prevalence of HTLV-1/2 in TB patients in Central-West Brazil and to perform a genetic characterisation of the respective isolates. Of the 402 patients, six (1.49%) were positive for anti-HTLV and five (1.24%; 95% confidence interval: 0.46-3.05) were infected with HTLV-1/2. Genetic characterisation demonstrated that the four HTLV-1 isolates belonged to the Transcontinental subgroup A of the Cosmopolitan subtype a and that the HTLV-2 isolate belonged to subtype a (HTLV-2a/c). The prevalence of HTLV infection observed in this study is higher than that observed in local blood donors and the HTLV-1 and 2 subtypes identified are consistent with those circulating in Brazil.

High prevalence of occult hepatitis B virus genotype H infection among children with clinical hepatitis in west Mexico

Studies on the prevalence of infection with hepatitis B virus (HBV) among children are scarce in Latin American countries, especially in Mexico. This study was aimed to investigate the prevalence of HBV infection, occult hepatitis B infection (OBI) and HBV genotypes among children with clinical hepatitis. In total, 215 children with clinical hepatitis were evaluated for HBV infection. HBV serological markers and HBV DNA were analysed. OBI diagnosis and HBV genotyping was performed. HBV infection was found in 11.2% of children with clinical hepatitis. Among these HBV DNA positive-infected children, OBI was identified in 87.5% (n = 21/24) of the cases and 12.5% (n = 3/24) were positive for both HBV DNA and hepatitis B surface antigen. OBI was more frequent among children who had not been vaccinated against hepatitis B (p < 0.05) than in those who had been vaccinated. HBV genotype H was prevalent in 71% of the children followed by genotype G (8%) and genotype A (4%). In conclusion, OBI is common among Mexican children with clinical hepatitis and is associated with HBV genotype H. The results show the importance of the molecular diagnosis of HBV infection in Mexican paediatric patients with clinical hepatitis and emphasise the necessity of reinforcing hepatitis B vaccination in children.

Molecular detection of Mayaro virus during a dengue outbreak in the state of Mato Grosso, Central-West Brazil

Mayaro virus (MAYV) is frequently reported in Pan-Amazonia. The aim of this study was to investigate the circulation of alphaviruses during a dengue outbreak in the state of Mato Grosso, Brazil. Serum samples from dengue-suspected patients were subjected to multiplex semi-nested reverse transcriptase polymerase chain reaction for 11 flaviviruses and five alphaviruses, to nucleotide sequencing and to viral isolation. MAYV was detected in 15 (2.5%) of 604 patients. Twelve were co-infected with dengue virus 4, which was isolated from 10 patients. The molecular detection of MAYV in dengue-suspected patients suggests that other arboviruses may be silently circulating during dengue outbreaks in Brazil.

Factors associated with the occurrence of Triatoma sordida (Hemiptera: Reduviidae) in rural localities of Central-West Brazil

This study estimates the factors of artificial environments (houses and peridomestic areas) associated with Triatoma sordida occurrence. Manual searches for triatomines were performed in 136 domiciliary units (DUs) in two rural localities of Central-West Brazil. For each DU, 32 structural, 23 biotic and 28 management variables were obtained. Multiple logistic regression analysis was performed in order to identify statistically significant variables associated with occurrence of T. sordida in the study areas. A total of 1,057 specimens (99% in peridomiciles, mainly chicken coops) of T. sordida were collected from 63 DUs (infestation: 47%; density: ~8 specimens/DU; crowding: ~17 specimens/infested DU; colonisation: 81%). Only six (0.6%) out of 945 specimens examined were infected with Trypanosoma cruzi. The final adjusted logistic regression model indicated that the probability of T. sordida occurrence was higher in DU with wooden chicken coops, presence of > 30 animals in wooden corrals, presence of wood piles and presence of food storeroom. The results show the persistence of T. sordida in peridomestic habitats in rural localities of Central-West Brazil. However, the observed low intradomestic colonisation and minimal triatomine infection rates indicate that T. sordida has low potential to sustain high rates of T. cruzi transmission to residents of these localities.

Geographic distribution of phlebotomine sandfly species (Diptera: Psychodidae) in Central-West Brazil

This study updates the geographic distributions of phlebotomine species in Central-West Brazil and analyses the climatic factors associated with their occurrence. The data were obtained from the entomology services of the state departments of health in Central-West Brazil, scientific collections and a literature review of articles from 1962-2014. Ecological niche models were produced for sandfly species with more than 20 occurrences using the Maxent algorithm and eight climate variables. In all, 2,803 phlebotomine records for 127 species were analysed. Nyssomyia whitmani,Evandromyia lenti and Lutzomyia longipalpiswere the species with the greatest number of records and were present in all the biomes in Central-West Brazil. The models, which were produced for 34 species, indicated that the Cerrado areas in the central and western regions of Central-West Brazil were climatically more suitable to sandflies. The variables with the greatest influence on the models were the temperature in the coldest months and the temperature seasonality. The results show that phlebotomine species in Central-West Brazil have different geographical distribution patterns and that climate conditions in essentially the entire region favour the occurrence of at least one Leishmania vector species, highlighting the need to maintain or intensify vector control and surveillance strategies.

Desenvolvimento do fruto da lichieira (Litchi chinensis Sonn.) 'Bengal'

Estudou-se o desenvolvimento do fruto da lichieira (Litchi chinensis Sonn.) 'Bengal'. Realizaram-se amostragens semanais, com início aos 35 dias após a antese e término no início da senescência dos frutos. A partir do 77º dia após a antese, os frutos foram decompostos em pericarpo, semente e arilo. A antese ocorreu na primeira semana de setembro. Foram ajustados modelos sigmoidais simples para acúmulo de matéria seca, comprimento e diâmetro. Para o acúmulo de matéria seca, uma fase inicial, de crescimento lento, prolongou-se até o 63º dia após a antese e coincidiu com um período de intensa queda natural de frutos. Do 63º ao 98º dia após a antese, houve uma fase de rápido acúmulo de matéria seca. Até o 77º dia, pericarpo e semente foram os principais responsáveis pelo acúmulo de matéria seca. Oitenta e oito por cento do comprimento e 65% do diâmetro máximos foram atingidos nesse período. Do 84º ao 98º dia após a antese, o desenvolvimento do fruto foi determinado basicamente pelo arilo. As dimensões e a matéria seca do fruto estabilizaram-se a partir do 98º dia após a antese. O ponto de colheita comercial dos frutos, caracterizado pela coloração avermelhada do pericarpo, ocorreu a partir do 112º dia após a antese. Verificou-se um quadro senescente nos frutos a partir do 119º dia após a antese.

Raleio de frutos em lichieira 'Bengal'

Originária da região sudeste da China, a lichieira tem apresentado significativo crescimento em área cultivada nos últimos anos devido aos excelentes sabor e aroma dos frutos. Porém, alternâncias de produção, associadas ao baixo vingamento de frutos, são problemas importantes da cultura. O raleio de frutos pode contribuir para a redução da alternância de produção e aumentar o percentual de frutos comercializáveis e de melhor qualidade, através do ganho em tamanho. Objetivou-se, neste trabalho, avaliar o efeito do raleio de frutos em lichieira 'Bengal' para as condições de cultivo em Viçosa, Minas Gerais. O experimento foi conduzido no delineamento experimental em blocos casualizados, com 5 tratamentos e 7 repetições, sendo cada planta uma repetição. Os tratamentos consistiram em diferentes intensidades de raleio manual representados pelo número de frutos deixados nas panículas do ramo terminal, sendo: T1: 3 frutos/ramo; T2: 6 frutos/ramo; T3: 9 frutos/ramo; T4: 12 frutos/ramo; T5: sem raleio (controle). Analisaramse o comprimento longitudinal e equatorial dos frutos (cm), a massa de fruto (g); a massa da casca, polpa e semente (g); o teor de sólidos solúveis totais (ºBrix); a acidez titulável da polpa (% ácido málico); a percentagem de matéria seca da polpa, casca e semente (%) e a percentagem de queda natural (%). Observou-se efeito do raleio somente para as variáveis teor de sólidos solúveis totais, percentagem de queda natural e massa de matéria seca da casca, não se justificando o raleio em frutos de lichieira.

Uso de tratamento hidrotérmico e ácido clorídrico na qualidade de lichia 'Bengal'

Um dos maiores problemas na pós-colheita da lichia é o escurecimento do pericarpo, cuja cor vermelha se torna totalmente escurecida em 48 horas, sob 25 ºC. Tecnologias que possam controlar o escurecimento do pericarpo são valiosas, e é o foco principal da pesquisa na área de pós-colheita. O objetivo deste trabalho foi avaliar a vida útil de lichias 'Bengal', armazenadas a 20 ºC e 82 %UR após o tratamento hidrotérmico e/ou imersão em solução de HCl. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 4 x 7, com 3 repetições, onde o primeiro fator correspondeu aos tratamentos: testemunha; imersão em HCl a 1%, por 6 minutos; tratamento hidrotérmico, com imersão em água a 52 ºC por 1 minuto, seguido de resfriamento em água a 10 ºC, por 6 minutos; e tratamento hidrotérmico, seguido de resfriamento em HCl a 1%, a 10 ºC, por 6 minutos. O segundo fator foram os períodos de armazenamento: 0; 1; 2; 3;6; 9 e 12 dias. A combinação entre tratamento hidrotérmico (52 ºC por 1 minuto) e resfriamento em HCl a 1% permite conservar a coloração das lichias 'Bengal' por até dois dias. Mesmo assim há escurecimento em 25% da superfície.

Ácido cítrico e quitosana na conservação de lichias 'Bengal'

Este trabalho teve como objetivo avaliar a aplicação de ácido cítrico em duas concentrações, associadas ou não à quitosana, na manutenção da qualidade de lichias 'Bengal'. Após a colheita e seleção, os frutos no estádio de maturação maduro foram imersos por 1 minuto nas seguintes soluções de ácido cítrico e de quitosana: [1] Testemunha - sem imersão; [2] ácido cítrico a 300 g L-1; [3] ácido cítrico a 300 g L-1 + 0,3% quitosana; [4] ácido cítrico a 300 g L-1 + 0,6% quitosana; [5] ácido cítrico a 600 g L-1; [6] ácido cítrico a 600 g L-1 + 0,3% quitosana; [7] ácido cítrico a 600 g L-1 + 0,6% quitosana. Após a imersão, os frutos foram colocados em gôndolas para escorrer o excesso de solução. Em seguida, foram armazenados em câmara fria, previamente higienizada, a 5ºC, durante 20 dias. O experimento foi conduzido seguindo um delineamento inteiramente casualizado, num esquema fatorial composto por sete soluções de recobrimento e cinco datas de amostragem. A cada cinco dias, foi avaliada a perda de massa fresca dos frutos, a coloração, o teor de antocianinas e a atividade das enzimas polifenoloxidase e peroxidase da casca. A solução de ácido cítrico a 600 g L-1, associada ou não à quitosana, e a combinação de quitosana 0,3% com 300 g L-1 de ácido cítrico foram as mais eficientes para a manutenção da cor avermelhada e a redução do escurecimento da casca de lichias 'Bengal' por 20 dias, a 5ºC.

Topworking of 'Bengal' lychee trees in the state of São Paulo, Brazil

This study aimed to evaluate the performance of 'Feizixiao', 'Nuomici', 'Heiye', 'Kway May Pink' and 'Bengal' lychee cultivars topworked onto bearing 'Bengal' trees. The experiments were carried out in commercial orchard at Rio das Pedras Farm in Jundiaí, state of São Paulo. The experimental design consisted of randomized blocks in a subdivided parcel arrangement, in which the parcel consisted of five cultivars and the sub-parcel consisted of six evaluation periods. Five replicates of three plants per parcel and six grafts per plant, (with two grafts per main branch) were used. The trees were approximately 10 years old propagated by air layering and planted with 6 x 4 m (416 plants/ha) spacing. The following characteristics were evaluated: success rate of the grafts, number of shoots, shoot length, number of nodes, number of leaves and chlorophyll content (SPAD). The control ('Bengal'/'Bengal') had the highest grafting success rate with 89.9%. On the other hand, 'Heiye', 'Feizixião', 'Nuomici' and 'Kway May Pink' had, respectively, 60.6, 55.0, 52.6 and 47.0% grafting success rates. All of the shoot grafts had normal growth with no signs of incompatibility. Therefore, the cultivars studied are compatible with 'Bengal' and may be used on commercial orchards.