Land use and cover changes and sand fly (Diptera: Psychodidae) assemblages in an emerging focus of leishmaniasis Maxcilene da Silva de Oliveira, Rosa Cristina Ribeiro da Silva, Antonia Suely Guimarães e Silva, Judson Chaves Rodrigues, Ronayce Conceição de Jesus Serrão Pimenta, Francisco Santos Leonardo, José Manuel Macário Rebêlo, Valéria Cristina Soares Pinheiro Medical and Veterinary Entomology, 2025 Land use and cover changes lead to fragmentation of the natural habitats of sand flies and modify the epidemiological profile of leishmaniasis. This process contributes to the infestation of adjacent rural settlements by vector sand fly species with different degrees of adaptation, promoting leishmaniasis outbreaks. This study aimed to assess land use and cover changes over a 12‐year period and investigate the diversity and abundance of sand fly assemblages in the rural area of Codó, Maranhão State, Brazil. Temporal analysis of land use and cover changes was conducted using Sentinel‐2 satellite imagery treated in QGIS software (free version 3.10) and classified using Orfeo Toolbox. Sand flies were sampled in alternate months between August 2022 and June 2023 using Centers for Disease Control and Prevention (CDC) light traps and white and black Shannon traps installed in peridomestic and extradomestic environments. Map images showed that the predominant land covers in 2012 and 2014 were dense and sparse vegetation, with few buildings. In 2021 and 2023, areas of sparse and dense vegetation were fragmented as new settlements were established. The entomological survey resulted in the capture of 3375 sand flies (CDC = 856, white Shannon = 650, black Shannon = 1969) belonging to 20 species. The most abundant species were Psychodopygus wellcomei Fraiha, Shaw & Lainson, 1971 (78.19%), followed by Nyssomyia whitmani (Antunes & Coutinho, 1939) (7.53%). Additionally, Ny. whitmani was the most abundant species (84.97%) in peridomestic environments, whereas Ps. wellcomei was the most abundant species (96.51%) in extradomestic environments. The sand fly assemblage was highly diverse, with a high abundance of competent vectors of Leishmania spp. These findings can promote community participation in surveillance and control efforts to prevent leishmaniasis cases.
Effect of pyriproxyfen on biological parameters and morphometry of Aedes aegypti Linnaeus, 1762 (Diptera: Culicidae) in the city of Manaus, Amazonas Aylane Tamara dos Santos Andrade, Cláudia Patrícia da Silva Tavares, Francisco Augusto da Silva Ferreira, André Correa de Oliveira, Suelen Costa Lima, Joaquim Ferreira do Nascimento Neto, Bianca Geovana Viana Pereira, Genilson Oliveira Rodrigues, Joelma Soares da Silva, Valéria Cristina Soares Pinheiro, Rosemary Aparecida Roque Acta Tropica, 2025 In Brazil, Aedes aegypti is the primary vector of arboviruses, and its control relies mainly on insecticide use. However, excessive application on these products has led to the selection of resistant populations. To address this challenge, products like Pyriproxyfen (PPF), an insect growth regulator, have been used as a viable alternative. In this context, the present study evaluated the susceptibility, resistance ratio, and biological changes of A. aegypti exposed to PPF. Samples were collected in eight neighborhoods using oviposition traps, and the Rockefeller strain was used as a susceptibility standard. Fecundity tests recorded a hatching rate of 72.4 % in the PPF groups, compared to 89.2 % in the control (p < 0.05), and fertility of 72.4 % for PPF compared to 89.2 % in the control (t = 204.5, df = 4, p < 0.05). Longevity was assessed in males, females, and couples (χ² = 20.35, df = 5, p > 0.05). Wing morphometric analyses were reinforced by Mahalanobis distance (1.7127; p < 0.001), Procrustes analysis (0.0064; p = 0.5027), and canonical variable analyses. The width of the cephalic capsules was greater in mosquitoes exposed to PPF (Mann-Whitney U = 369; p < 0.0099). The emergence inhibition rate ranged from 65.33 ± 4 to 100 ± 0 for the Rockefeller strain and from 59.33 ± 4 to 88.66 ± 2 for the field population, with a resistance ratio of 0.68. The study concludes that the A. aegypti population in Manaus, remains susceptible to PPF, and the observed alterations were not significant enough to compromise the vector's biology.
Retrospective Study of Arbovirus Circulation in Northeast Brazil in 2019 and 2022: Insights into the Re-Emergence of DENV-3 and the Co-Infection of DENV-1 and CHIKV Sêmilly Suélen da Silva Sousa, Ana Cecília Ribeiro Cruz, Carine Fortes Aragão, Glennda Juscely Galvão Pereira Cereja, Sandro Patroca da Silva, Raira Maria Morais de Sousa, Murilo Tavares Amorim, Eliana Vieira Pinto da Silva, Bruno Tardelli Diniz Nunes, Valéria Cristina Soares Pinheiro Viruses, 2025 Arboviruses transmitted by Aedes aegypti cause high number of cases and deaths annually. The aim was to investigate the presence of the presence of Dengue (DENV), Zika (ZIKV) and Chikungunya (CHIKV) viruses in endemic areas of Maranhão, northeastern Brazil. The study was carried out in Caxias, Codó, Peritoró, and São Mateus do Maranhão in 2019 (Caxias) and 2022. The blood samples were subjected to RNA extraction and then tested by RT-qPCR. Cell culture was used to attempt viral isolation and subsequent sequencing. In total, 171 samples were analyzed (32 from 2019, 18.7%) and 72 (42.1%) were found to have arboviruses: 68 (39.7%) from Caxias; 2 (1.1%) from Codó; 1 (0.6%) from Peritoró; and 1 (0.6%) from São Mateus. Overall, 85.3% (n = 58) of the positive samples were infected with DENV-1, 4 (four) (5.9%) with DENV-2 (Caxias), 1 (one) (1.5%) with DENV-3 (Caxias), and in 6 (six) (7.3%) samples CHIKV was detected, with one co-infection of DENV-1 and CHIKV (Caxias). The DENV-1 genotype V and the ECSA genotype of CHIKV were characterized in samples from Caxias. The detection of DENV-1, DENV-2, DENV-3, and more CHIKV in the interior of Maranhão alerts to the importance of virological studies in these areas.
Entomovirological Surveillance in Aedes (Stegomyia) aegypti Linnaeus, 1762 and Aedes (Stegomyia) albopictus Skuse, 1894 (Diptera, Culicidae) in new housing areas in eastern Maranhão, Brazil L. S. Ribeiro, A. M. Palacio-Cortés, M. A. Navarro-Silva, I. M. S. Souza, S. A. S. Silva, T. P. C. Santos, R. S. Silva, A. S. Lima, F. S. Leonardo, J. A. C. Zequi, V. C. S. Pinheiro, J. Soares-da-Silva Brazilian Journal of Biology, 2025 Aedes aegypti is the primary vector of dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV), while Aedes albopictus is considered a potential vector for these arboviruses. Therefore, monitoring the spatial and temporal distribution of these vectors through entomovirological surveillance is essential. This study aimed to conduct entomovirological monitoring of Ae. aegypti and Ae. albopictus populations in newly established housing areas in eastern Maranhão, Brazil. Eggs and adults were collected monthly for one year across residential complexes comprising approximately 3,000 households. Detection of DENV, ZIKV, and CHIKV was performed using real‑time reverse transcription polymerase chain reaction (RT‑qPCR). A total of 122,378 Aedes spp. eggs were collected. The Ovitrap Positive Index (OPI) varied across locations, with similar averages (71.0%, 67.6%, and 67.9%), and higher values recorded from February to May. The Egg Density Index (EDI) showed pronounced variation, reaching a peak of 376.1. A total of 304 adult mosquitoes were collected, of which 205 were Ae. aegypti (67.43%). Heat maps indicated wide distribution of mosquitoes across the three study areas, with higher densities and hotspots during the rainy months. No arboviruses were detected in the analyzed female pools. The study demonstrated the population dynamics of Ae. aegypti and Ae. albopictus in new housing developments and confirmed the effectiveness of ovitraps in estimating vector density, with an overall OPI of 68.83%.
Phlebotomine sand fly (Diptera: Psychodidae) fauna, blood meal source, and detection of Leishmania (Kinetoplastida: Trypanosomatidae) DNA in the Gurupi Biological Reserve, Eastern Amazon, Brazil Judson Chaves Rodrigues, Rosa Cristina Ribeiro-da-Silva, Antonia Suely Guimarães-e-Silva, Maxcilene da Silva de Oliveira, Bruno Leite Rodrigues, Ronayce Conceição de Jesus Serrão Pimenta, Eunice Aparecida Bianchi Galati, Valéria Cristina Soares Pinheiro Journal of Medical Entomology, 2024 This study was conducted in the Gurupi Biological Reserve (REBIO-Gurupi), the largest area of Amazon rainforest in Maranhão State, Brazil. The objectives were to survey the sand fly (Diptera: Psychodidae) fauna of REBIO-Gurupi, identify blood meal sources, and investigate the presence of Leishmania (Ross, 1903) (Kinetoplastida: Trypanosomatidae) DNA. Individuals were collected using Centers for Disease Control (CDC) light traps and black and white Shannon traps in May and Jun 2022 and Jan 2023. DNA was extracted from female sand flies and subjected to amplification and sequencing of cytochrome b molecular marker (CYTB) for identification of blood meal sources and the first internal transcribed spacer (ITS-1) of ribosomal DNA for Leishmania detection. A total of 514 sand flies individuals were sampled, of which 93 were identified at the genus or series level (9 taxa) and 421 were identified at the species level (24 taxa). Psychodopygus davisi (Root, 1934) (41.1%), Nyssomyia antunesi (Coutinho, 1939) (10.3%), and Psychodopygus (Mangabeira, 1941) Chagasi Series Barretto, 1962 (9.7%) were the most frequently collected. Human (Homo sapiens, Primates, Hominidae) and tapir (Tapirus terrestris, Perissodactyla, Tapiridae) DNA was detected in 10 female sand flies. Leishmania (Leishmania) infantum Cunha and Chagas, 1937 DNA was detected in 2 specimens of Ps. davisi. Given the presence of vectors of Leishmania in REBIO-Gurupi, it is imperative to conduct more comprehensive studies on the interactions among sand flies, Leishmania, and pathogen reservoirs in the area.
Spatial-temporal risk clusters, social vulnerability, and identification of priority areas for surveillance and control of cutaneous leishmaniasis in Maranhão, Brazil: an ecological study Romário de Sousa Oliveira, Karen Brayner Andrade Pimentel, Rosa Cristina Ribeiro da Silva, Antonia Suely Guimarães-e-Silva, Maria Edileuza Soares Moura, Valéria Cristina Soares Pinheiro Journal of Medical Entomology, 2024 Cutaneous leishmaniasis (CL) is a neglected disease widely distributed in Maranhão, Brazil and presents a significant public health problem. However, its transmission dynamics and determining factors are not clearly understood. In this context, geospatial technologies help interpret the process. This study, then, characterized the space–time dynamics and the influence of social vulnerability on CL in an endemic area in Northeast Brazil. This is an ecological study about new cases of CL in Maranhão, from 2007 to 2020, obtained directly from the Notifiable Diseases Information System. The incidence rate was smoothed using a spatial empirical Bayesian method. Subsequently, global and local Moran statistics and their association with social vulnerability indicators were determined. Disease distribution was not random but grouped in space and time. All Social Vulnerability Index domains were positively correlated with the CL incidence. A likely cluster was detected in western Maranhão (P &lt; 0.001), which encompassed 18 municipalities, from January 2007 to December 2013, with a high relative risk (5.06). The research findings suggest that planning public health actions and allocating resources should be prioritized in these areas to help effectively reduce the incidence of the disease.
Mortality from neglected tropical diseases in the state of Maranhão, Brazil: a guidance for health planning in vulnerable areas R. S. Oliveira, K. B. A. Pimentel, F. E. Almeida-de-Souza, V. C. S. Pinheiro, J. M. T. Bezerra Brazilian Journal of Biology, 2024 Neglected tropical diseases (NTD) are chronic infectious diseases affecting low-income populations (mainly in tropical and subtropical climates), characterized by high morbidity and low mortality. This study described the epidemiology of mortality from NTDs in the state of Maranhão, Brazil. Data from the Brazilian Mortality Information System evidenced 2,642 deaths from NTDs between 2001 and 2021; 31.13% were related to leishmaniasis (mainly the visceral form) and 20.82% to leprosy. A total of 211 municipalities in Maranhão had registered mortality due to NTDs. We identified, high-risk spatial and spatiotemporal conglomerates in the western and southern areas of Maranhão, comprising mostly municipalities with high social vulnerability and low human development. Integrated mapping of NTDs may allow the development of public intervention policies and is an important strategy to control and eliminate NTDs in the most affected populations.
Prediction of visceral leishmaniasis incidence using the Seasonal Autoregressive Integrated Moving Average model (SARIMA) in the state of Maranhão, Brazil K. B. A. Pimentel, R. S. Oliveira, C. F. Aragão, J. Aquino Júnior, M. E. S. Moura, A. S. Guimarães-e-Silva, V. C. S. Pinheiro, E. G. R. Gonçalves, A. R. Silva Brazilian Journal of Biology, 2024 Visceral leishmaniasis (VL) is an infectious disease predominant in countries located in the tropics. The prediction of occurrence of infectious diseases through epidemiologic modeling has revealed to be an important tool in the understanding of its occurrence dynamic. The objective of this study was to develop a forecasting model for the incidence of VL in Maranhão using the Seasonal Autoregressive Integrated Moving Average model (SARIMA). We collected monthly data regarding VL cases from the National Disease Notification System (SINAN) corresponding to the period between 2001 and 2018. The Box-Jenkins method was applied in order to adjust a SARIMA prediction model for VL general incidence and by sex (male or female) for the period between January 2019 and December 2013. For 216 months of this time series, 10,431 cases of VL were notified in Maranhão, with an average of 579 cases per year. With regard to age range, there was a higher incidence among the pediatric public (0 to 14 years of age). There was a predominance in male cases, 6437 (61.71%). The Box-Pierce test figures for overall, male and female genders supported by the results of the Ljung-Box test suggest that the autocorrelations of residual values act as white noise. Regarding monthly occurrences in general and by gender, the SARIMA models (2,0,0) (2,0,0), (0,1,1) (0,1,1) and (0,1,1) (2, 0, 0) were the ones that mostly adjusted to the data respectively. The model SARIMA has proven to be an adequate tool for predicting and analyzing the trends in VL incidence in Maranhão. The time variation determination and its prediction are decisive in providing guidance in health measure intervention.
Natural infection of Aedes aegypti by Chikungunya and Dengue type 2 Virus in a transition area of north-northeast Brazil Carine Fortes Aragão, Valéria Cristina Soares Pinheiro, Joaquim Pinto Nunes Neto, Eliana Vieira Pinto da Silva, Glennda Juscely Galvão Pereira, Bruna Laís Sena do Nascimento, Karoline da Silva Castro, Ariadne Mendonça Maia, Clistenes Pamplona Catete, Lívia Carício Martins, Wanderli Pedro Tadei, Sandro Patroca da Silva, Ana Cecília Ribeiro Cruz Viruses, 2019
Circulation of Chikungunya virus in Aedes aegypti in Maranhão, Northeast Brazil Carine Fortes Aragão, Ana Cecília Ribeiro Cruz, Joaquim Pinto Nunes Neto, Hamilton Antonio de Oliveira Monteiro, Eliana Vieira Pinto da Silva, Sandro Patroca da Silva, Aylane Tamara dos Santos Andrade, Wanderli Pedro Tadei, Valéria Cristina Soares Pinheiro Acta Tropica, 2018
Influence of abiotic factors on the effectiveness of Bacillus thuringiensis israelensis (Berliner, 1911) against larvae of Aedes aegypti (Linnaeus, 1762) Revista Cubana De Medicina Tropical, 2014
