Sergio Ibáñez-Bernal

First record in America of Aedes albopictus naturally infected with dengue virus during the 1995 outbreak at Reynosa, Mexico

Abstract Mosquito collections were conducted during a dengue outbreak in Reynosa, Tamaulipas, Mexico, July‐December 1995. A total of 6694 adult mosquitoes (four genera and nine species) were captured, of which 2986 (78.3% females and 21.7% males) were Aedes albopictus and 2339 (39.7% females and 60.3% males) were Ae.aegypti. These two species comprised 84.2% of the total collection. Specimens were grouped into pools, nearly 50% of them processed for detection of virus by cythopathic effect in C6‐36 and VERO cell cultures and by haemagglutination test. Five pools gave positive haemagglutin‐ation reactions and were examined by immunofluorescence using monoclonal antibodies to flavivirus and to dengue virus. One pool of ten Ae.albopictus males was positive for dengue virus: serotypes 2 and 3 were identified by serotype‐specific monoclonal antibodies arid confirmed by RT‐PCR. This is the first report of Ae.albopictus naturally infected with dengue virus in America. Also, it is the very first time Ae.albopictus males have been found infected with dengue virus in the wild.

Infección natural de chinches Triatominae con Trypanosoma cruzi asociadas a la vivienda humana en México

OBJETIVO: Informar el porcentaje de infeccion natural de las especies de triatominos que habitan con mayor frecuencia el medio domestico y peridomestico en Mexico, asi como dar a conocer las localidades de colecta por estado. MATERIAL Y METODOS: Se recibieron muestras de chinches Triatominae en el Departamento de Entomologia del Instituto de Diagnostico y Referencia Epidemiologicos, para su determinacion taxonomica y la busqueda parasitoscopica de Trypanosoma cruzi, provenientes de 14 estados del pais, de enero de 1993 a diciembre de 1999. Se analizaron en conjunto los resultados obtenidos en esos anos. RESULTADOS: De una muestra de 5 399 ejemplares, fueron 13 las especies de triatominos asociadas a las viviendas. El porcentaje de infeccion natural tuvo una amplia variacion entre las especies. De las estudiadas, nueve se encontraron con infeccion natural; el mayor porcentaje de infeccion corresponde a Triatoma pallidipennis, T. picturata, Rhodnius prolixus y T. longipennis. Los estados con mayor porcentaje de infeccion fueron Nayarit, Morelos y Michoacan. Se presentaron nuevos registros estatales de Triatoma dimidiata, T. gerstaeckeri, T. longipennis, T. mexicana y T. pallidipennis y uno local de Pastrongylus rufotuberculatus. Ademas, se informa por primera vez la infeccion natural en algunas de ellas. CONCLUSIONES: Se debe poner mayor enfasis en el estudio de la biologia y aspectos bionomicos de los triatominos y realizar una vigilancia permanente para tener los registros de distribucion actualizados, asi como para conocer los indices de infeccion natural por T. cruzi, de las especies domiciliarias, peridomiciliarias y de las que estan en proceso de adaptacion a la vivienda humana.

Current Knowledge of Leishmania Vectors in Mexico: How Geographic Distributions of Species Relate to Transmission Areas

Leishmaniases are a group of vector-borne diseases with different clinical manifestations caused by parasites transmitted by sand fly vectors. In Mexico, the sand fly Lutzomyia olmeca olmeca is the only vector proven to transmit the parasite Leishmania mexicana to humans, which causes leishmaniasis. Other vector species with potential medical importance have been obtained, but their geographic distributions and relation to transmission areas have never been assessed. We modeled the ecological niches of nine sand fly species and projected niches to estimate potential distributions by using known occurrences, environmental coverages, and the algorithms GARP and Maxent. All vector species were distributed in areas with known recurrent transmission, except for Lu. diabolica, which appeared to be related only to areas of occasional transmission in northern Mexico. The distribution of Lu. o. olmeca does not overlap with all reported cutaneous leishmaniasis cases, suggesting that Lu. cruciata and Lu. shannoni are likely also involved as primary vectors in those areas. Our study provides useful information of potential risk areas of leishmaniasis transmission in Mexico.

First record of Lutzomyia evansi (Nuñez-Tovar 1924) in Mexico (Diptera: Psychodidae, Phlebotominae)

The phlebotomine sand fly Lutzomyia evansi is recorded in Mexico for the first time. This species is a suspected vector of Leishmania infantum in other parts of its geographical range and was captured in a focus of American visceral leishmaniasis where the principal vector, Lu. longipalpis sensu lato, was also found. The relative public health importance of the two species in the study area (Chiapas state, Southern Mexico) is discussed.

Dengue virus in bats from southeastern Mexico.

To identify the relationship between landscape use and dengue virus (DENV) occurrence in bats, we investigated the presence of DENV from anthropogenically changed and unaltered landscapes in two Biosphere Reserves: Calakmul (Campeche) and Montes Azules (Chiapas) in southern Mexico. Spleen samples of 146 bats, belonging to 16 species, were tested for four DENV serotypes with standard reverse transcriptase polymerase chain reaction (RT-PCR) protocols. Six bats (4.1%) tested positive for DENV-2: four bats in Calakmul (two Glossophaga soricina, one Artibeus jamaicensis, and one A. lituratus) and two bats in Montes Azules (both A. lituratus). No effect of anthropogenic disturbance on the occurrence of DENV was detected; however, all three RT-PCR-positive bat species are considered abundant species in the Neotropics and well-adapted to disturbed habitats. To our knowledge, this study is the first study conducted in southeastern Mexico to identify DENV-2 in bats by a widely accepted RT-PCR protocol. The role that bats play on DENVs ecology remains undetermined.

Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae) in coffee agroecosystems.

The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.)], Finca Argovia (613 m a.s.l.) and Teotihuacán del Valle (429 m a.s.l.). Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp.

Reappearance of Aedes aegypti (Diptera: Culicidae) in Lima, Peru

We report here the reappearance of Aedes aegypti in the Rimac district, and summarize the history of this mosquito species in Peru since its first detection in 1852. On March 17 2000 were found Ae. aegypti and Culex quinquefasciatus in Mariscal Castilla town, Flor de Amancaes, San Juan de Amancaes, El Altillo and Santa Rosa in the Rimac district, Lima Province.

New Records and Descriptions of Mexican Moth Flies (Diptera: Psychodidae, Psychodinae)

Abstract The following species are recorded by first time in Mexico: Lepidiella albipeda (Rapp, 1945b), L. matagalpensis (Collantes and Martínez-Ortega, 1998), Australopericoma caudata (Satchell, 1955), Balbagathis sylvatica Quate, 1994, Paramormia furcata (Kincaid, 1899), Psychoda cinerea Banks, 1894, P. lativentris Berdén, 1952, P. savaiiensis Edwards, 1928, and P. tothastica Quate, 1955. Aditionally, some state records of Clogmia albipunctata (Williston, 1893), Psychoda alternata Say, 1824, and P. alternicula Quate, 1955, are provided. The female of Lepidiella albipeda (Rapp), the male of Balbagathis sylvatica Quate, 1994, and the male and female of one previously unknown species of the genus Psychoda Latreille, 1796, are described and illustrated by first time. Additionally, Telmatoscopus sobrinus Quate, 1955 and Duckhousiella corniculata Vaillant, 1973 of North America are transferred to the genus Paramormia Enderlein.

Establishment of Aedes aegypti (L.) in mountainous regions in Mexico: Increasing number of population at risk of mosquito-borne disease and future climate conditions.

The study was conducted in the central region of Veracruz Mexico, in the metropolitan area of Xalapa. It is a mountainous area where Aedes aegypti (L.) is not currently endemic. An entomological survey was done along an elevation gradient using the Ae. aegypti occurrences at different life cycle stages. Seven sites were sampled and a total of 24 mosquito species were recorded: 9 species were found in urban areas, 18 in non-urban areas with remnant vegetation, and 3 occurred in both environments. Ae. aegypti was found only in the urban areas, usually below 1200m a.s.l., but in this study was recorded for the first time at 1420m a.s.l. These occurrences, together with additional distribution data in the state of Veracruz were used to developed species distribution models using Maxlike software in R to identify the current projected suitable areas for the establishment of this vector and the human populations that might be affected by dengue transmission at higher elevations. Its emergence in previously unsuitable places appears to be driven by both habitat destruction and biodiversity loss associated with biotic homogenization. A border study using data from the edges of the vectors distribution might allow sensitive monitoring to detect any changes in this mosquitos distribution pattern, and any changes in the anthropic drivers or climate that could increase transmission risk.

A standardized sampling method to estimate mosquito richness and abundance for research and public health surveillance programmes

Programmes involving mosquito research and surveillance are normally focused on the study of aquatic larval stages, but sampling methods are varied and not systematized, which hinders the comparative analysis of ecological data. A standardized method for assessing the richness and abundance of mosquito larval populations of value for the analysis of mosquito diversity is presented. Based on the study of all the aquatic sites in a one hectare sample area with a proportional number of dips according to the size of the aquatic habitat, comparative data can be obtained on species richness and relative abundance of species found between pairs of sites or in the same area at different times. This technique provides information on the total mosquito fauna at each site, helps recognize species of medical importance and estimates the abundance of each species; parameters that are not estimated by the current entomological indexes used in surveillance programmes. The quality of the inventory is obtained by estimation of the efficiency effort. Procedures for calculating alpha, beta and gamma diversity are presented. The technique was validated in a natural and an urban zone at La Mancha, Veracruz, Mexico, over two years of sampling made during different climatic seasons.