Brazil's first free-mating laboratory colony of Nyssorhynchus darlingi

Abstract INTRODUCTION: The lack of highly-productive Nyssorhynchus darlingi laboratory colonies limits some studies. We report the first well-established laboratory colony of Ny. darlingi in Brazil. METHODS: Mosquitoes were collected from Porto Velho and were reared at the Laboratory of Fiocruz/RO. After induced mating by light stimulation in the F1 to F6, the subsequent generations were free mating. Larvae were reared in distilled water and fed daily until pupation. RESULTS: In 11 generations, the colony produced a high number of pupae after the F5 generation. CONCLUSIONS: These results demonstrate the potential for permanently establishing Ny. darlingi colonies for research purposes in Brazil.

Ecdysis-related pleiotropic neuropeptides expression during Anopheles albimanus development / Expresión de neuropéptidos pleiotrópicos asociados con ecdisis durante el desarrollo del mosquito Anopheles albimanus

Abstract: Objective: To analyze the transcription pattern of neuropeptides in the ontogeny of a malaria vector, the mosquito Anopheles albimanus. Materials and methods: The transcription pattern of Crustacean CardioActive peptide (CCAP), corazonin, Ecdysis Triggering Hormone (ETH), allatostatin-A, orcokinin, Insulin Like Peptide 2 (ILP2), Insulin Like Peptide 5 (ILP5) and bursicon was evaluated using qPCR on larvae (1st - 4th instar), pupae and adult mosquitoes. Results: Unlike in other insects, transcripts of CCAP (70.8%), ETH (60.2%) and corazonin (76.5%) were expressed in 4th instar larvae, probably because these three neuropeptides are associated with the beginning of ecdysis. The neuropeptide ILP2 showed higher transcription levels in other stages and orcokinin decreased during the development of the mosquito. Conclusion: The CCAP, corazonin and ETH neuropeptides are potential targets for the design of control strategies aimed at disrupting An. albiamnus larval development.

Resumen: Objetivo: Describir la expresión de neuropéptidos durante la ontogenia del mosquito vector de la malaria Anopheles albimanus. Material y métodos: Se midió la expresión de CCAP, corazonina, ETH, allatostatina, orcokinina, ILP2, ILP5 y bursicon en larvas de primer (2mm), segundo (4mm), tercer (5mm) y cuarto (6mm) estadio, pupas y mosquitos adultos, mediante qPCR. Resultados. A diferencia de otros insectos en donde, CCAP, corazonina y ETH se expresan principalmente en estadios pupales, en An. albimanus se expresaron mayoritariamente en larvas de cuarto estadio, CCAP tuvo 70.8% de expresión relativa, corazonina 76.5% y ETH 60.2%. ILP2 fue el neuropéptido que más se expresó en el primer, segundo y tercer estadio y orcokinina disminuyó durante el desarrollo del mosquito. Conclusión. Los péptidos estudiados se expresaron en todos los estadios de desarrollo del mosquito. Sin embargo, su expresión varió en cada uno de ellos. Los neuropéptidos CCAP, corazonina y ETH, que son esenciales para la transformación de lavas a pupas, pueden ser blancos potenciales para el diseño de estrategias de control dirigidas a interrumpir el desarrollo larvario de An. albimanus.

Aceites esenciales y sus componentes como una alternativa en el control de mosquitos vectores de enfermedades / Essential oils and their components as an alternative in the control of mosquito vectors of disease

Resumen Más de la mitad de la población humana está expuesta a contraer infecciones transmitidas por mosquitos. El cambio climático y la aparición de cepas resistentes a los insecticidas tradicionalmente utilizados han motivado la búsqueda de nuevos agentes capaces de controlar las poblaciones de mosquitos. Los aceites esenciales han resultado ser eficaces agentes repelentes y larvicidas. El objetivo de este trabajo fue revisar las investigaciones llevadas a cabo en los últimos años sobre la actividad larvicida de los aceites esenciales y sus componentes contra mosquitos de los géneros Aedes, Anopheles y Culex, así como los últimos reportes sobre su posible mecanismo de acción.

Abstract More than half of the human population is exposed to mosquito-borne infections. Climate change and the emergence of strains resistant to traditionally used insecticides have motivated the search of new agents for mosquito population control. Essential oils have been effective repellents and larvicidal agents. The aim of this work was to review research studies conducted in recent years on the larvicidal activity of essential oils and their components against Aedes, Anopheles and Culex mosquitoes, as well as the latest reports about their possible mechanism of action.

Especies de Anopheles presentes en el departamento del Putumayo y su infección natural con Plasmodium / Anopheles species present in the department of Putumayo and their natural infectivity with Plasmodium

Introducción. El departamento del Putumayo es una región endémica para malaria, o paludismo, causada principalmente por Plasmodium vivax . Los vectores en esta región incluyen Anopheles darlingi , el cual se ha encontrado solamente en el municipio de Puerto Leguízamo, y recientemente se incriminaron como vectores en Puerto Asís a las especies An. rangeli y An. oswaldoi . Objetivo. El propósito del trabajo fue determinar el papel de An. benarrochi B en la transmisión de malaria en este departamento, ya que se reporta como la especie más abundante que pica a los humanos. Materiales y métodos. Se recolectaron larvas y adultos de Anopheles spp. entre el 2006 y el 2008 en los municipios Puerto Leguízamo y Puerto Asís, y se obtuvieron secuencias del gen ITS-2 y del gen mitocondrial COI para confirmar las determinaciones taxonómicas por morfología. Se practicó la prueba ELISA para establecer la infección por P. vivax y P. falciparum. Resultados. Se identificaron 6.238 individuos correspondientes a 11 especies: An. albitarsis s.l. (1,83 %), An. benarrochi B (72,35 %), An. braziliensis (0,05 %), An. costai (0,06 %), An. darlingi (19,37 %), An. mattogrossensis (0,08 %), An. neomaculipalpus (0,13 %), An. oswaldoi s.l. (0,64 %), An. punctimacula (0,03 %), An. rangeli (5,12 %) y An. triannulatus s.l. (0,34 %). Se evaluaron 5.038 adultos por ELISA y 5 se encontraron positivos para P. vivax 210 y VK 247, todos pertenecientes a la especie An. benarrochi B. Conclusión. Los resultados sugieren que An. benarrochi B juega un papel en la transmisión de P. vivax en el departamento de Putumayo, dada su alta atracción por los humanos y su infección natural con Plasmodium spp.

Introduction: Putumayo is considered an endemic region for malaria transmission, mainly due to Plasmodium vivax. The vectors in this region are Anopheles darlingi , which has been found only in the municipality of Puerto Leguízamo, and An. rangeli and An. oswaldoi s.l. , which were recently incriminated as vectors in Puerto Asís. Objective: The purpose of this study was to determine the role of An. benarrochi B in malaria transmission in Putumayo, given that it is the most abundant species biting humans. Materials and methods: Collections of immature and adult stages of Anopheles spp. were made between 2006 and 2008 in the municipalities of Puerto Leguízamo and Puerto Asís in Putumayo, and sequences of internal transcribed spacer 2 ( ITS-2 ) of ribosomal DNA and the mitochondrial gene COI were obtained to confirm the morphological determinations. ELISA was carried out for P. vivax and P. falciparum infectivity. Results: A total of 6,238 specimens were identified, distributed in 11 species: An. albitarsis s.l. (1.83%), An. benarrochi B (72.35%), An. braziliensis (0.05%), An. costai (0.06%), An. darlingi (19.37%), An. mattogrossensis (0.08%), An. neomaculipalpus (0.13%), An. oswaldoi s.l. (0.64%), An. punctimacula (0.03%), An. rangeli (5.12%), and An. triannulatus s.l. (0.34%). A total of 5,038 adults were assessed by ELISA and 5 were found positive for P. vivax 210 and VK 247, all belonging to An. benarrochi B. Conclusion: The results suggest that An. benarrochi B plays a role in the transmission of P. vivax in Putumayo due to its high human contact and natural infection with Plasmodium sp.

Primer registro de Anopheles (Nyssorhynchus) oswaldoi B y Anopheles (Nys) albitarsis F en la cuenca del río Caura, Estado Bolívar, Venezuela / First record of anopheles (Nyssorhynchus) oswaldoi B y anopheles (Nys) albi-tarsis F from the Caura river basin, Bolívar State, Venezuela

Se registran por primera vez anopheles albitarsis F y anopheles oswaldoi B recolectadas en localidades de los municipios Sucre y Cedeño del estado Bolívar. Los análisis morfométricos de hembras adultas mostraron que los caracteres analizados en las manchas claras y oscuras de la vena Costa del ala y los tarsómeros de las patas posteriores para An. albitarsis F caen dentro de los rangos reportados para An. marajora sensu lato, mientras que para An. oswaldoi B los rangos de variación de los caracteres medidos están dentro del rango reportado para An. oswaldoi s.l., An. oswaldoi sensu stricto de Brasil y An. konderi. Sin embargo, el análisis de ADN mitocondrial (región código de barras, 658 pb) mostró una divergencia genética entre An. oswaldoi B y An. oswaldoi s.s. de 3,2%, mientras entre An. albirtarsis F y An. marajoara s.s. esta fue de 5,2%, valores que están por encima de los limites propuestos para delimitación de especies.

Anopheles albitarsis F and Anopheles oswaldoi B were first recorded from collections in Sucre and Cedeño Municipalities, Bolivar State. Morphometric analysis of dark and pale spots on wing Costa and hind tarsomeres of adult females, showed that the range of variation for An. albitarsis F are within the reported ranges for An. marajoara sensu latu For An. oswaldoi B the range of variation are within the ranges reported for An. oswaldoi s.l., An. oswaldoi sensu stricto from Brazil and An. konderi. DNA mitochondrial analysis (Barcode region 658 bp) showed 3.2% of genetic divergence between An. oswaldoi B and An. oswaldoi s.s., while this divergence was 5.2% between An. albirtarsis F and An. marajoara s.s. Both these values are above the proposed limits for species delimitation.

Caracterización de la transmisión de la malaria por Plasmodium vivax en la región fronteriza de Panamá con Costa Rica en el municipio de Barú, Panamá / Characterization of Plasmodium vivax malaria transmission at the border of Panamá and Costa Rica

Introducción. Pocos estudios describen los factores asociados con la dinámica de transmisión de la malaria, o paludismo, por Plasmodium vivax en las regiones endémicas de Panamá. Objetivo. Caracterizar la dinámica de transmisión de la malaria producida por P. vivax en la región fronteriza de Panamá con Costa Rica. Materiales y métodos. Se llevó a cabo un estudio observacional, descriptivo y transversal. Se evaluaron la incidencia parasitaria anual, el índice de láminas positivas y el índice anual de exámenes de sangre. Se identificaron los anofelinos vectores, y se caracterizaron sus criaderos preferenciales, densidad larvaria e índice de picada/hombre/noche. Se hizo búsqueda pasiva y activa de casos sospechosos mediante examen de gota gruesa. Resultados. De 10.401 muestras de gota gruesa, 83 resultaron positivas para P. vivax. El 84 % de los casos provenía de zonas rurales, el 79 % constituía una población económicamente activa, la mediana de edad fue de 36 años y, la media, de 30 años. El 58,5 % de los casos fueron de sexo masculino. La incidencia parasitaria anual fue de 4,1 por 1.000 habitantes; el índice de láminas positivas fue de 0,8 % y el índice anual de exámenes de sangre fue de 51,9 %. El 65,0 % de los casos diagnosticados registró entre 100 y 2.000 parásitos/μl de sangre. Se identificaron los mosquitos vectores Anopheles albimanus y An. punctimacula. Conclusión. Es necesario el seguimiento de estudios entomológicos, el fortalecimiento de la vigilancia epidemiológica, la consideración de los factores de riesgo y la realización de un trabajo en coordinación con las autoridades de salud de Costa Rica, para controlar la malaria en esta región.

Introduction. Few studies have described the factors associated with Plasmodium vivax transmission dynamics in endemic regions from Panamá. Objective. Malaria transmission dynamics produced by P. vivax were characterized at the border between Panamá and Costa Rica. Materials and methods. In the municipality of Barú, an observational, descriptive and cross-sectional study was undertaken to measure the annual parasite index (API), slide positivity index (SPR), and the annual blood examination rate (ABER). The most frequent symptoms and signs in malaria patients were recorded. The anopheline species were identified in the area and the preferred larval habitats, the density of larval populations in the larval habitats and the bites/human/night were characterized. Results. Of a total of 10,401 thick smear blood samples, 83 were positive for P. vivax. Of these, 84% came from rural areas and 79% were from economically active individuals. The median and average ages were 36 and 30 years, respectively, and 58.5% of the malaria cases were male. API was 4.1/1,000 inhabitants; SPR was 0.8% and ABER was 51.9%. Of the diagnosed cases, 54% showed blood parasitemias ranging between 100-2,000 parasites/μl. The majority of the cases were observed in May and June. Two mosquito vector species were identified-- Anopheles albimanus and An. punctimacula. Conclusion. These observations indicate the advisibility of continued entomological studies, strengthening of epidemiological surveillance, consideration of additional risk factors and evaluation of work performance in the border region. This will require coordination with health authorities of both countries to control malaria in this region.

[Survey of climatic condition of Malaria disease outbreak in Iran using GIS]

Malaria as a mosquito-borne disease is largely dependent on climatic conditions. Temperature, rainfall and relative humidity are considered as climatic factors affecting the geographical distribution of this disease. These climatic factors have definite roles not only in the growth and proliferation of the mosquito Anopheles but also in the parasite Plasmodium activity. The purpose of this study was to find in which regions of Iran climatic conditions favour spread of malaria. Data on 3 climatic factors, including the mean monthly temperature, rainfall and mixed ratio of humidity, obtained from 31 synoptic meteorological stations during the 30-year period 1975-2005 were used. By running the informative filters through map algebra tools in the Geographical Information System [GIS], the synoptic meteorological stations were classified into 4 groups in terms of climatic conditions favouring activity and proliferation of the mosquito Anopheles and the parasite Plasmodium. Then the regions were interpolated in terms of climate risk of malaria incidence using the tension Spiline interpolation method. The maps of climatic potential malaria risk indicated that the southern provinces including Hormozgan, Bushehr and Khuzestan, southern parts of Sistan-Balouchistan province, such as Chabahar and Nikshahr, as well as Northern provinces of the country, including Mazandaran and Gilan, have the highest climatic potential for risk of malaria spread. On the other hand, provinces in the North Western region, including West and East Azarbaijan, Ardebil, Kurdistan and Zanjan, have the lowest climatic potential risk of malaria spread. Further analysis of the data showed that a large segment of the population is living in regions with medium- to high-risk zones. The findings of this study can be used when designing malaria control programs to identify different regions in terms of climate-based malaria risk. The presented risk map of malaria in this study is completely based on climatic factors. The disconformity between these presented climate-based maps and the observed high-risk map is due to such factors as socioeconomic and lifestyle changes, as well as border problems [foreign subjects entering the country]

Nuevos registros de mosquitos (Diptera Culicidae) para el estado Bolívar, Venezuela: Dos de ellos nuevos para el país / New records of mosquitoes (Diptera Culicidae) for the state of Bolivar, Venezuela: Two of them new to the country

En el presente trabajo se hace referencia por primera vez para el estado Bolívar de diez y nueve especies de mosquitos (Diptera Culicidae), pertenecientes a diez (10) géneros: Anopheles, Chagasia, Culex, Aedes, Mansonia, Coquilletidia, Uranotaenia, Psorophora, Limatus y Wyeomyia, de las subfamilias Anophelinae y Culicinae. Dos de estas especies, son citadas por primera vez para Venezuela: Chagasia bonneae Root, 1927 y Chagasia ablusa Harbach, 2009.

First report of 19 Culicidae species (Diptera: Culicidae) from Bolivar State is made, belonging to 10 genera of Anophelinae and Culicinae: Anopheles, Chagasia, Culex, Aedes, Mansonia, Coquilletidia, Uranotaenia, Psorophora, Limatus and Wyeomyia. Chagasia bonneae Root, 1927 and Chagasia ablusa Harbach, 2009 are reported for the first time in Venezuela.

Anopheles gambiae no Brasil – 1930 a 1940

Fred L. Soper e D. Bruce Wilson lideraram uma campanha sanitária no Nordeste brasileiro que culminou com a erradicação, em tempo recorde – apenas 35 meses –, do mais eficiente dentre os vetores da malária, o mosquito Anopheles gambiae. Considerado leitura obrigatória para os interessados em saúde pública no Brasil, o relatório final dessa campanha – que descreve detalhadamente os procedimentos e métodos de trabalho sob o ponto de vista de seus diretores – foi originalmente publicado em inglês, em 1943. Pouco depois, em 1945, o relatório ganhou uma edição em português, mas não uma tradução fiel. Ela se voltava para as atividades do Serviço de Malária do Nordeste e a questão dos doentes de malária, enquanto o original era centrado nas ações da Fundação Rockefeller e na campanha de erradicação do mosquito. Decidiu-se, então, retraduzir o original – encontrado hoje em dia somente na seção de obras raras de bibliotecas especializadas –, incorporando alguns elementos de destaque da primeira versão em português

Anopheles gambiae no Brasil: 1930 a 1940 / Anopheles gambiae in Brazil - 1930-1940

Fred L. Soper e D. Bruce Wilson lideraram uma campanha sanitária no Nordeste brasileiro que culminou com a erradicação, em tempo recorde – apenas 35 meses –, do mais eficiente dentre os vetores da malária, o mosquito Anopheles gambiae. Considerado leitura obrigatória para os interessados em saúde pública no Brasil, o relatório final dessa campanha – que descreve detalhadamente os procedimentos e métodos de trabalho sob o ponto de vista de seus diretores – foi originalmente publicado em inglês, em 1943. Pouco depois, em 1945, o relatório ganhou uma edição em português, mas não uma tradução fiel. Ela se voltava para as atividades do Serviço de Malária do Nordeste e a questão dos doentes de malária, enquanto o original era centrado nas ações da Fundação Rockefeller e na campanha de erradicação do mosquito. Decidiu-se, então, retraduzir o original – encontrado hoje em dia somente na seção de obras raras de bibliotecas especializadas –, incorporando alguns elementos de destaque da primeira versão em português

Haematophageous vector monitoring in Djibouti city from 2008 to 2009: first records of culex pipiens ssp. torridus [iglisch], and anopheles sergentii [theobald]

The Horn of Africa represents a region formerly known to be highly susceptible to mosquito-borne infectious diseases. In order to monitor and analyze the current presence and threat of vector mosquitoes, continuous and standardized trapping using CDC light traps without an additional CO2-generator has been carried out at six selected monitoring sites located in Djibouti City, from August 2008 until December 2009. An overall of 620 haematophageous Diptera were trapped, 603 [97.3%] were mosquitoes, 10 [1.6%] were sand flies, and 7 [1.1%] were biting midges, respectively. Genus distribution of mosquitoes revealed that 600 [99.5%] were Culex spp., 2 [0.3%] were Anopheles sergentii, and 1 [0.2%] was Aedes aegypti. Culex species were represented by Cx. quinquefasciatus [78.5%], and Cx. pipiens ssp. torridus [21.5%]. The later species was first detected focally in early December 2009 showing a strongly increasing population density resulting in a maximum trap rate of 25 mosquitoes per trap night. Sand flies were all Sergentomyia antennata, and biting midges of the genus Culicoides were represented by C. nubeculosus [71.4%] and C. vexans [28.6%]. The findings included the first records for Cx. pipiens ssp. torridus and An. sergentii in Djibouti. However, none of the captured female Culex spp, the known vector for West Nile Virus, showed positive results for viral nucleic acids using WNV RT-real time PCR system. Also, females An. sergentii were Plasmodium falciparum and P. vivax circumsporozoite protein negative

Mosquito fauna [Diptera: culicidae] and seasonal activity in Makka al Mukarramah region, Saudi Arabia

From March 2004 to February 2006, a mosquito survey was conducted in Makka Al Mukarrama Region, in the western part of Saudi Arabia, and 19 species which belong to 4 genera, were collected: Aedes [2 species], Anopheles [8 species], Culex [8 species] and Culiseta [1 species]. The mosquitoes were Aedes caspius, Ae. aegypti, Anopheles d'thali, An. gambiae, An. multicolor, An. rhodesiensis, An. sergenti, An. stephensi, An. subpictus, An. turkhudi, Culex arbieeni, Cx. laticinctus, Cx. pipiens, Cx. quinquefasciatus, Cx. sinaiticus, Cx. tigripes, Cx. tritaeniorhynchus, Cx. univittatus and Culiseta longiareolata. Cx. arbieeni was reported for the first time in Saudi Arabia from Al Taif District. The physical properties of water of mosquito's larval breeding sites showed the total dissolved salts [TDS] varied between 70-15552 ppm, pH ranged between 5.4-11.2 and water temperature varied between 15°C in winter to 40.7°C in summer. There was no correlation between these physical properties and the distribution of mosquito larvae. Light traps collected 1858 mosquitoes, and adult Culex were the most prevalent as 1658 [89.24%] were collected, followed by 121 [6.51%] Aedes, 68 [3.66%] Anopheles and 11 [0.59%] Culiseta. The effects of temperature and rainfall on seasonal abundance of mosquitoes in the study area are discussed

Morphological aspect of the midgut of anopheles aquasalis (Curry, 1932) Insecta: Diptera / Aspecto morfológico del intestino medio de anopheles aquasalis (Curry, 1932) Insecta: Diptera

The midgut of adult female Anopheles aquasalis presents a narrow anterior or thoracic region and a distensible posterior or abdominal region constituted by the epithelium formed by a cell layer whose apical portion presents microvilli and the basal portion, a basal labyrinth. The thoracic region revealed heterogeneous cellular staining affinity mainly by the presence of acidic components. The ultrastructural aspect showed columnar cells with the presence of the vesicle, mitochondria, endoplasmic reticulum and secreting cells. The abdominal region of the midgut revealed an irregular epithelium whose cells presented a basophilic cytoplasm and acidophil granules. It was also found secreting and/or basal cells with narrow cytoplasm. The ultrastructural observation of this region demonstrated cells with evident nucleus, endoplasmic reticulum and mitochondria. Larger vesicles and small granules were found distributed throughout the cytoplasm. The basal lamina that supports the epithelium presented a generally irregular aspect and the muscle fibers have longitudinal and circular organization and were found separating the epithelium from the haemocel. This study will contribute to analyses on the vector mosquito-parasite interaction mechanism in this specimen.

La seccion media del intestino de la hembra de Anopheles aquasalis presenta una estrecha region anterior o toráxica y una region posterior o abdominal constituida por el epitelio formado por una camada de células cuya porcion apical presenta microvilosidades y la porcion basal presenta un laberinto basal. La region toráxica reveló afinidad de tintura celular principalmente para componentes acídicos. El aspecto ultra estructural mostró células columnares con la presencia de la vesícula, mitocondrias, retículo endoplasmático y células secretoras. La region abdominal del intestino medio reveló un epitelio irregular con células con citoplasma basófilo y granulos acidófilos. También se encontraron células secretoras y/o básales con citoplasma estrecho. La observacion ultra estructural de la region mostró células con núcleos, retículo endoplasmático y mitocondrias evidentes. Vesículas largas y granulos pequeños fueron encontrados distribuidos por todo el citoplasma. La lámina basal que apoya el epitelio presentó un aspecto irregular y las fibras musculares tienen organizacion longitudinal y circular y separan el epitelio del hemocele. Este estudio contribuirá al análisis del mecanismo de interaccion entre el mosquito y el parásito en este espécimen.

Prevalence of mosquito species in Chhura block of Raipur district of Chhattisgarh state.

Mosquitoes act as vectors for several diseases including malaria and filaria. In Indian scenario, Chhattisgarh is endemic for both the diseases. The present study on prevalence of mosquito population in block Chhura of Raipur district of Chhattisgarh state was undertaken between August 2002 and March 2004 to asses the distribution pattern of various species of mosquitoes and their seasonal variations. Indoor resting mosquitoes were collected from five villages by aspirator tube in the morning (06:00-08:00 hr) using torchlight. Adult mosquitoes were identified using standard morphological and pictorial keys. Altogether 11 species belonging to three genera viz., Anopheles (7 species), Armigeres (1 species) and Culex (3 species) were recorded during study period. Average man-hour mosquito density was high in February 2003 (62.15) & March 2003 (69.35) and declined gradually till June 2003. From July 2003, it started rising again and reached a peak in August (94.10)-September (91.60) 2003. The vector species i.e. Anopheles culicifacies and Anopheles annularis were recorded high in rainy and winter seasons.

Encontro de larvas de Anopheles (Nyssorhynchus) argyritarsis em criadouros artificiais no Estado de Mato Grosso / Anopheles (Nyssorhynchus) argyritarsis larvae found in artificial breeding sites in the State of Mato Grosso

Cita-se o encontro de formas imaturas de culicídeos em caixas d’água colocadas no nível do solo. Foram encontradas larvas de Anopheles argyritarsis e Aedes albopictus no município de Várzea Grande (MT). Considera-se que estes recipientes artificiais possam constituir locais adicionais utilizáveis como criadouros de anofelinos.

The finding of immature forms of culicid mosquitoes in water tanks at ground level is reported. Anopheles argyritarsis and Aedes albopictus were found in the municipality of Várzea Grande (MT). It is considered that these artificial containers may constitute additional locations that anophelines can use as breeding sites.

Anopheles gambiae s.s. breeding in polluted water bodies in urban Lagos, southwestern Nigeria.

BACKGROUND & OBJECTIVE: Urban malaria is on the rise in Nigeria due to rapid industrialisation and developmental activities. A study was undertaken in Lagos, Nigeria to study the Anopheles breeding in polluted water bodies. METHODS: Anopheles larval breeding habitats were surveyed and water samples from 24 larval breeding sites from four strategic areas in urban Lagos were analysed. The relationship between eight abiotic variables (pH, dissolved oxygen, conductivity, hardness, nitrate, total dissolved solids, turbidity and oil) and density of Anopheles larvae were investigated. The levels of heavy metals (Zn, Co, Cu, Pb, Mn, Fe, Hg and Ni) pollution were analysed by Atomic Absorption Spectrophotometry. RESULTS: Morphological and PCR analysis of 2358 anopheline larvae revealed only the presence of two members of the Anopheles gambiae complex consisting of 93.1% Anopheles gambiae s.s. and 6.9% An. arabiensis. Multiple regression analysis revealed a significant association between occurrence of An. arabiensis larvae and two independent variables: pH and turbidity but not for An. gambiae s.s. The levels of three heavy metals: Fe, Cu and Pb from more than half of the sites surveyed were three times higher than the values obtained in natural breeding sites of An. gambiae s.s. from a rural area of Lagos. Over 85% of An. gambiae s.s. larvae were found in water bodies characterised by low dissolved oxygen (<3 mg/L), high conductivity (>900 uS/cm), turbidity (>180 FAU), oil (>11 mg/L) and heavy metals: Fe, Cu, and Pb (>0.4 mg/L). INTERPRETATION & CONCLUSION: These results indicate that An. gambiae s.s. is adapting to a wide range of water pollution in this urban area. The survival of the mosquito in widespread polluted water bodies across Lagos metropolis could be responsible for the rise in the incidence of malaria.

Spatial distribution and habitat characterisation of Anopheles larvae along the Kenyan coast.

BACKGROUND & OBJECTIVES: A study was conducted to characterise larval habitats and to determine spatial heterogeneity of the Anopheles mosquito larvae. The study was conducted from May to June 1999 in nine villages along the Kenyan coast. METHODS: Aquatic habitats were sampled by use of standard dipping technique. The habitats were characterised based on size, pH, distance to the nearest house, coverage of canopy, surface debris, algae and emergent plants, turbidity, substrate, and habitat type. RESULTS: A total of 110 aquatic habitats like stream pools (n=10); puddles (n=65); tire tracks (n=5); ponds (n=5) and swamps (n=25) were sampled in nine villages located in three districts of the Kenyan coast. A total of 7,263 Anopheles mosquito larvae were collected, 63.9% were early instars and 36.1% were late instars. Morphological identification of the III and IV instar larvae by use of microscopy yielded 90.66% (n=2377) Anopheles gambiae Complex, 0.88% (n=23) An. funestus, An. coustani 7.63% (n=200), An. rivulorum 0.42% (n=11), An. pharoensis 0.19% (n=5), An. swahilicus 0.08% (n=2), An. wilsoni 0.04% (n=1) and 0.11% (n=3) were unidentified. A subset of the An. gambiae Complex larvae identified morphologically, was further analysed using rDNA-PCR technique resulting in 68.22% (n=1290) An. gambiae s.s., 7.93% (n=150) An. arabiensis and 23.85% (n=451) An. merus. Multiple logistic regression model showed that emergent plants (p = 0.019), and floating debris (p = 0.038) were the best predictors of An. gambiae larval abundance in these habitats. Interpretation & conclusion: Habitat type, floating debris and emergent plants were found to be the key factors determining the presence of Anopheles larvae in the habitats. For effective larval control, the type of habitat should be considered and most productive habitat type be given a priority in the mosquito abatement programme.

Introduction, transmission and aggravation of malaria in desert ecosystem of Rajasthan, India.

BACKGROUND & OBJECTIVES: Malaria is an important public health problem in northwestern desert part of Rajasthan. Since desert malaria is seasonal or unstable, there is a need to study its epidemiology in the totality to address factors like how malaria is introduced into desert every year and what are desert-specific transmission risk factors leading to epidemics? METHODS: Twenty-six villages in irrigated, semi-irrigated and non-irrigated settings of the desert have been selected. Periodic investigations were undertaken in all the seasons from 2001 through 2002 to determine causes of introduction of disease, the factors involved in its transmission and the epidemic risk factors. Standard methods/procedures for mosquito collection, preservation and identification and for parasitological studies were employed. Rainfall data were analysed and correlated. Results: Importation of malaria infection through individuals was the major cause of introduction of disease in all the 12 villages showing some initial load of infection. Areas having higher population of cattle in relation to humans (human to cattle ratio of 1:25) had less transmission of disease (ratio of primary to secondary cases 1:3) as compared to relatively less cattle (human to cattle ratio 1:3) resulting into high transmission of disease with 1:47 ratio of primary to secondary cases. Introduced through migration, prospective transmission of malaria was observed as a resultant interaction of density of three components namely malaria cases, vector density and cattle to human ratio. Rainfall more than average when coupled with more cases of imported malaria leads to the eruption of malaria epidemics. INTERPRETATION & CONCLUSION: Importation of malaria cases was the major cause of seasonal introduction of malaria in the desert. This initial or primary parasitic load available in a village leads to a particular transmission quantum depending upon the density of vectors, human and cattle population at a particular time. Areas with more imported cases when coupled with profuse vector population lead to epidemic malaria situations in the desert.

Soil analysis around anopheline breeding habitats in north-western Thailand.

The epidemiology of malaria is largely dependent on its vector habitat. Each species of Anopheles larvae has a specific habitat requirement for its development. Anopheline mosquitoes are common throughout Thailand and utilize a wide variety of habitats. The dominant malaria vectors in Thailand are An. dirus, An. maculatus, and An. minimus. The relationship between soil chemical components and the particular species of anopheline in their specific aquatic habitats was studied from September 2002 to July 2003 at Ban Khun Huay, Ban Pa Dae, and Ban Tham Seau in the Mae Sot district, Tak Province, Thailand. Mapping of each habitat was performed using a Global Positioning System unit. A total count of 2,130 laboratory reared adult Anopheles were collected from 138 habitats categorized into 11 different types identified into 18 species from larval sampling in three villages. An. dirus, An. maculatus, and An. minimus were found 5.26%, 10.70%, and 55.31%, respectively, along with other minor species. Drainage and/or season seemed to be associated with the presence of An. dirus, An. maculatus, An. minimus, An. jamesii, An. sawadwongporni, and An. peditaeniatus. Chemical tests: pH, aluminum, magnesium, calcium, and ferric iron showed some associations with the presence of Anopheles. Only drainage was found to be a parameter associated with the presence of An. minimus.

Laboratory estimation of the effects of increasing temperatures on the duration of gonotrophic cycle of Anopheles albimanus (Diptera: Culicidae)

The increase of malaria transmission in the Pacific Coast of Colombia during the occurrence of El Niño warm event has been found not to be linked to increases in the density of the vector Anopheles albimanus, but to other temperature-sensitive variables such as longevity, duration of the gonotrophic cycle or the sporogonic period of Plasmodium. The present study estimated the effects of temperature on duration of the gonotrophic cycle and on maturation of the ovaries of An. albimanus. Blood fed adult mosquitoes were exposed to temperatures of 24, 27, and 30ºC, held individually in oviposition cages and assessed at 12 h intervals. At 24, 27, and 30ºC the mean development time of the oocytes was 91.2 h (95 percent C.I.: 86.5-96), 66.2 h (61.5-70.8), and 73.1 h (64-82.3), respectively. The mean duration of the gonotrophic cycle for these three temperatures was 88.4 h (81.88-94.9), 75 h (71.4-78.7), and 69.1 h (64.6-73.6) respectively. These findings indicate that both parameters in An. albimanus are reduced when temperatures rose from 24 to 30ºC, in a nonlinear manner. According to these results the increase in malaria transmission during El Niño in Colombia could be associated with a shortening of the gonotrophic cycle in malaria vectors, which could enhance the frequency of man-vector contact, affecting the incidence of the disease.