Hourly frequency and seasonality of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) on São Luís Island, Maranhão, Brazil

This article presents the hourly and seasonal distribution of the Lutzomyia longipalpis sand fly captured on S?o Luís Island, Maranh?o State. A total of 11,200 specimens were captured during monthly use of CDC light traps indoors and in animal sheds, between 6:00 PM and 6:00 AM, in 1996 and 1997. The sand fly behaved as an annual species, with a high frequency year-round, while it was most abundant during the rainy season (57.2%) as compared to the dry season (42.8%). The highest frequencies during the rainy season occurred in January and April and in the dry season in July and November. The species was found all night long, mainly between 6:00 PM and 10:00 PM in animal sheds and between 8:00 PM and 2:00 AM indoors.     

Phlebotomine sandfly species from an American visceral leishmaniasis area in the Northern Rainforest region of Pernambuco State, Brazil

The aim of this study was to identify the fauna of phlebotomine sandflies in an area with incidence of American visceral leishmaniasis (AVL) in S?o Vicente Férrer, a municipality (county) located in the northern Zona da Mata in Pernambuco State, Brazil. Sandfly captures were conducted monthly for four nights/month from December 2002 to November 2003, by means of manual captures (with a Shannon trap) and by CDC light traps. A total of 23,156 specimens of phlebotomines sandflies were collected in a remnant of the Atlantic rainforest, houses, and animal shelters. Lutzomyia complexa was the most prevalent species, with a frequency of 62.5% (14,445/23,156), followed by Lutzomyia migonei, with 33.2% (7,677/23,156). No Lutzomyia longipalpis (the main vector of Leishmania chagasi in Brazil and the Americas) was found in the target area. Some specimens were dissected, but no Leishmania parasites were found.     

Host feeding preferences of sandflies in rural area, Southern Brazil

OBJECTIVE: To investigate the fauna and host feeding preferences of sandflies as for domestic animals in an endemic area of American cutaneous leishmaniasis. METHODS: The sandflies collections were carried out from 8:00 pm to 12:00 am in an area 40 meters away from one of the residences in a farm in Southern Brazil, between January and April, 2004. Collection was performed using four Falc?o light traps, placed 5 m apart from each other beside a cage, each one of them containing an animal bait (swine, dog, rabbit, and chicken). RESULTS: A total of 1,697 specimens of sandflies were collected as follows: Nyssomyia whitmani, Pintomyia fischeri, Migonemyia migonei, Nyssomyia neivai, Pintomyia pessoai and Psathromyia shannoni. The prevalent species was N. whitmani. There were no feeding preferences of sandflies as for the animals studied. CONCLUSIONS: N. whitmani and P. fischeri are opportunistic species and female insects probably adjust their eating habits to host availability, suggesting eating eclecticism of these insects in anthropic environments.     

Sandflies (Diptera, Psychodidae) from an endemic leishmaniasis area in the cerrado region of the State of Maranh?o, Brazil]

This article presents a list of ten sandfly species from the genus Lutzomyia Fran?a, 1924 found in the counties of Aldeias Altas, Capinzal do Norte, Caxias, Codó, Coelho Neto, Timbiras, Timon and Tuntum in northeastern Maranh?o, Brazil. Presence of sandflies was associated with cases of visceral and cutaneous leishmaniasis. Some 377 specimens were captured indoors with CDC light traps and 1491 specimens in the peridomicile. The species were: Lutzomyia cortelezii, Lutzomyia evandroi, Lutzomyia goiana, Lutzomyia intermedia, Lutzomyia lenti, Lutzomyia longipalpis, Lutzomyia longipennis, Lutzomyia squamiventris, Lutzomyia termitophila and Lutzomyia whitmani. The most abundant species was L. longipalpis (67. 4% and 70.2%) followed by L. whitmani (31.0% and 24.7%). L. longipalpis was captured both indoors and outdoors in all the months studied.     

Seasonal and nocturnal domiciliary human landing/biting behaviour of Lutzomyia (Lutzomyia) evansi and Lutzomyia (Psychodopygus) panamensis (Diptera; Psychodidae) in a periurban area of a city on the Caribbean coast of eastern Venezuela (Barcelona; Anzoátegui State)

In recent years, in addition to American cutaneous leishmaniasis (ACL), a significant number of cases of American visceral leishmaniasis (AVL) have been reported in periurban areas of Barcelona city (Anzoátegui State, Venezuela). We studied the bionomics of Lutzomyia (Lutzomyia) evansi and Lutzomyia (Psychodopygus) panamensis, possible vectors of AVL and ACL, respectively, in El Rincón, a periurban village of that city. To evaluate the seasonal domiciliary landing/biting activity of sandflies on human bait, a house was chosen in El Rincón. Landing catches were carried out between 18:00 and 06:00, once a month for a year. The results show the presence of 2 species, Lu. (Lu.) evansi (89.9%) and Lu. (Psy.) panamensis (10.1%). Lu. evansi was most abundant in the months of October and July, associated with the bimodal cycle of annual rainfall in the area. Maximum landing/biting activity of Lu. evansi was observed at 24:00 and 03:00. These findings suggest that at this time of the year and at these hours there is heightened risk of the transmission of AVL. Lu. panamensis monthly abundance also shows a direct association with rainfall and maximum landing/biting activity was observed between 02:00 and 03:00. The lower domiciliary abundance of Lu. panamensis suggests its greater importance in the extradomiciliary transmission of ACL.     

Ecology of Lutzomyia (Nyssomyia) whitmani in an urban area in Maringá, Paraná, Brazil

OBJECTIVES: To study the fauna, hours of activity and seasonality of phlebotomines in forest animal habitats in the Ingá Park, on the urban perimeter of the municipality of Maringá, Paraná State, Brazil. METHODS: Phlebotomines were collected on the urban perimeter using Shannon traps from 6:00 p.m. to 6:00 a.m. and Falc?o traps from 8:00 p.m. to 12:00 midnight, on two nights per month from October 1998 to September 2000. The Shannon traps were installed close to forest animal habitats and on the banks of the Moscados stream; the Falc?o traps were placed in shelters for captive birds, forest mammals and reptiles. RESULTS: The Shannon traps yielded 13,656 phlebotomines, with predominance of Lutzomyia whitmani (98.7%). The Falc?o traps yielded 4,040 phlebotomines, with L. whitmani again predominating (96.3%). L. whitmani was most frequently found between 12:00 midnight and 2:00 a.m. in the Shannon traps. This species was most frequently collected in the months of August (55.1%) in the Shannon traps, and in March 1999 (19.2%), November 1999 (15.9%) and August 2000 (20.6%) in the Falc?o traps. More phlebotomines were collected in Falc?o traps installed in shelters for captive mammals (84.0%). CONCLUSION: There was a clear predominance of L. whitmani in the Ing Park. The greatest frequency of L. whitmani was in August from Shannon traps, and in March and November from Falc?o traps. The peak activity of L. whitmani took place between 12:00 midnight and 2:00 a.m.     

Diversity and species composition of sand flies (Diptera: Psychodidae) in a Venezuelan urban focus of cutaneous leishmaniasis

The present study examined the spatial and temporal abundance and diversity of phlebotomine sand flies in an area of Venezuela that is an ancient focus of leishmaniasis. The study was conducted in 6 stations in urban localities in Trujillo City, located in northwestern Venezuela (9 degrees 22' 24" N, 70 degrees 26' 08" W), which is located in a mountain range in the Andean ecoregion (altitude = 600-1,010 m). During 1995-99, entomological surveys were conducted after and before the rainy season. Shannon light traps were operated from 1800 to 2000 h in peridomestic site trap locations. Twelve species were captured, and Lutzomyia youngi, L. ovallesi, L. scorzai, L. gomezi, L. lichyi, and L. shannoni occurred at all localities in each year. The abundance of these species showed low variation over time but high variation between localities. The S?rensen similarity index, used to compare diversity between years within each locality, ranged from 0.60 at Carmona to 0.84 at La Hacienda. Sand fly communities exhibited annual variation in species richness and diversity. Variations were affected more by changes in species abundance than by changes in species composition. Lutzomyia ovallesi, L. lichyi, and L. scorzai had the highest coefficient of variation between years (63, 38, and 23%, respectively).     

Light and hens as attraction factors of Nyssomyia whitmani in a rural area, Southern Brazil

OBJECTIVE: To verify the influence of traps with electric light and hens as factors that attract sandflies and compare results between capture methods. METHODS: The study was conducted in the Palmital Farm, Southern Brazil. Sandfly collections were conducted with Falc?o traps and an electric aspirator, fortnightly, between 8 p.m. and 11 p.m. in the presence or absence of light and hens in peridomiciliary areas, from September 1998 to June 1999. RESULTS: A total of 43,767 specimens from eight species of sandflies were collected: Nyssomyia whitmani, N. neivai and Migonemyia migonei constituting 99.9% of the total collected, with predominance of N. whitmani. The number of this species collected inside the hen's shed in the presence of hens (21,045) was greater than in their absence (10,434). In the presence of hens, with distinct intensities of light, a larger number of N. whitmani samples were collected with 3W light. In the presence of hens and light (3W), the number of N. whitmani collected with the electric aspirator (5,141) was superior to that collected with the Falc?o trap (1,675). In the absence of light, with or without the presence hens, there was no difference between the numbers of N. whitmani collected with the electric aspirator or the Falc?o trap. CONCLUSIONS: Hens and electric light together attract more N. whitmani to peridomicilary areas. The number of N. whitmani collected with an electric aspirator inside a hen's shed with the presence of hens and light is greater than those collected with a Falc?o trap in the same conditions.     

Vertical stratification of phlebotomine sandfly fauna (Diptera,Psychodidae) in a primary non-flooded forest of the Central Amazon,Amazonas State,Brazil

Studies on the vertical stratification of phlebotomine sandfly fauna were conducted in a non-flooded primary forest at a Tropical Forest Experimental Station of the National Institute of Amazonian Research from October 1998 to March 1999. CDC light traps were placed at one, 10, and 20 meters above ground. A total of 2,859 sandflies were captured, belonging to the Lutzomyia (99.93%) and Brumtomyia (0.07%) genera, represented by 38 species. In the Lutzomyia gender, the most frequent sub-gender was Nyssomyia (43.4%), followed by Psychodopygus (22.8%). Lutzomyia umbratilis, L. anduzei, L. rorotaensis, L. trichopyga, and L. olmeca nociva predominated at one meter above ground, while L. davisi, L. infraspinosa, L. umbratilis, L. trichopyga, and L. anduzei predominated at 10 meters. L. anduzei, L. tuberculata, L. dendrophyla, and L. dreisbachi were the most abundant species at 20 meters. L. umbratilis, which appeared at all three levels of vertical stratification, has great epidemic significance as a vector of Leishmania (Viannia) guyanensis.     

Sandflies in rural localities in northwest Paraná State, Brazil

This study reports the results from sandfly captures at six sites in a rural area of Japurá, Paraná State, Brazil, showing the vector's presence indoors, outdoors, and in residual forest. Sandfly captures were performed with Falc?o traps from 8:00 AM to 3:00 PM. At sites 195, 223, 236, and 527, three captures were performed at different times from December 2007 to January 2009. At sites 175 and 218, captures were performed from January to December 2008. 8,453 sandflies were captured, with an average of 155.40 specimens per hour. Nyssomyia neivai was the predominant species. Most sandflies were captured in domestic animal shelters (75.91 per hour) and in ciliary forest (38.45 per hour) during the hottest and rainiest months, in the outdoor environment with accumulation of organic matter and inadequate disposal of household wastewater. The study emphasizes the need for regular outdoor cleaning around households and building domestic animal shelters far from residences.     

Risk factors associated with asymptomatic infection by Leishmania chagasi in north-east Brazil

Various factors have been associated with a predisposition to the development of clinical American visceral leishmaniasis (AVL). However, little information is available about the factors that predispose to asymptomatic infection. To identify the risk factors associated with asymptomatic infection, a study was carried out between July 1997 and June 1998 on children aged 0-5 years in the districts of Vila Nova and Bom Viver in the municipality of Raposa in the island of S?o Luís, State of Maranh?o, Brazil. A questionnaire containing socioeconomic, demographic and epidemiological data was used. The delayed-type hypersensitivity (DTH) test was carried out on 639 children in the first phase, and on 572 in the second, 7 months after the first survey, using Leishmania amazonensis antigen. Infection was determined by enzyme-linked immunosorbent assay (ELISA) in 638 children during the first phase, and in 572 during the second. Six outcome measures were used: initial prevalence, final prevalence and incidence, each determined by DTH and ELISA. The incidence of infection was 10.8% when determined by DTH and 28.5% when determined by ELISA. After adjustment for confounding variables using Cox regression, infection by L. chagasi was associated with child's age (> or = 2 years), location of the dwellings (Vila Nova) and reporting of relatives with AVL. Bathing outside the house and playing outdoors between 18:00 and 20:00 were identified as risk factors in some analyses but not in others. Presence of intra- and peridomestic Lutzomyia sandflies and animals such as dogs or chickens in the house or in the neighbourhood appeared as risk factors in some analyses but in others they unexpectedly seemed to protect from infection. Malnutrition was not found to be associated with infection.     

Blood feeding sources and peridomiciliation of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Psychodidae, Phlebotominae)

A precipitin test was employed to study the alimentary tract content of Lutzomyia longipalpis in the intra- and peridomiciliary environments in the municipality of Raposa, Maranh o State, a transmission area for visceral leishmaniasis or kala azar. Out of 2,240 female sandflies captured, 547 (24.4%) had fed on vertebrate blood, with the following proportions: avian (87.9%); rodent (47.2%); human (42.4%); canine (27.6%); opossum (26.6%); and equine (22.5%). Based on a survey of 120 human dwellings, chickens were found to be the most common domestic animals in the peridomicile (28.3%), followed by dogs (21.7%), cats (17.5%), donkeys (13.3%), pigeons (7.5%), rabbits (3.3%), ducks (3.3%), and horses, mallards, and pigs (1.7% each). Synanthropic animals included opossums (39.3%), followed by rats (37.9%), bats (14.3%), raccoons (3.6%), foxes (2.1%), snakes (1.4%), and frogs (1.4%). The peridomiciliary presence of domestic and synanthropic animals as well as sandflies that had fed on human, opossum, and canid blood supports the hypothesis that kala azar transmission has been taking place in the anthropic environment in the municipality of Raposa.     

Preliminary check list of species from the genus Lutzomyia, França, 1924

This paper presents a preliminary check list of Lutzomyia species from Maranh?o State. The information derives from data gathered in the scarce literature on the distribution patterns of neotropical phlebotomines. There are 40 species reported in the State. Most are Amazonian in their distribution, while others come from the savanna domain of Central Brazil or have a widespread distribution in the neotropics. This can be explained by Maranh?o's transitional position between the North, Northeast, and Central South of the country. Of the species of sandflies reported, seven are currently considered vectors for cutaneous and visceral leishmaniases.     

Leishmaniasis in Brazil. 8. Observations on the phlebotomine fauna of an area highly endemic for cutaneous leishmaniasis, in the Serra dos Carajas, Pará State

A study has been made of the phlebotomine fauna in an area highly endemic for Leishmania braziliensis braziliensis in forest of the Serra dos Carajás, Pará State, Brazil, using human and rodent bait.A total of 23 different species were encountered, including 2 new sandflies, to be described at a later date. Over 92% of the total catch off man was made up by species of the genus Psychodopygus. Of these, Ps. wellcomei formed 65% of the total caught off man and 24·5% of the total off rodents. This species is of particular interest in view of its tendency to bite man throughout daylight hours.Once more we have confirmed that although Lutzomyia flaviscutellata may be the predominent species feeding on rodents, it is rarely taken biting man.Very few sandflies were captured above ground-level; and attempts to find the daytime resting places for the major man-biting species were unsuccessful.The relationship of rainfall to sandfly density is discussed. It is concluded that the population density of certain forest species may depend not so much on the quantity of rainfall, but more on the amount of water which persists in the topsoil in a given region.     

Leishmaniasis in Brazil. XXIV. Natural flagellate infections of sandflies (Diptera: Psychodidae) in Pará State, with particular reference to the r?le of Psychodopygus wellcomei as the vector of Leishmania braziliensis braziliensis in the Serra dos Carajás

Between July 1983 and December 1984 natural flagellate infections were found in 114 (1%) of 11,586 female phlebotomine sandflies (Diptera: Psychodidae) of 21 species. A further 1084 females of 17 other species were not infected. Identification of the organisms on a number of occasions confirms the exclusive parasite/vector relationship of Leishmania mexicana amazonensis/Lutzomyia flaviscutellata and Le. braziliensis braziliensis/Psychodopygus "wellcomei". Undescribed or unidentified Leishmania spp. were isolated from Lu. shawi, Lu. ubiquitalis, Lu. whitmani, Ps. hirsutus, Ps. paraensis Ps. "wellcomei", and trypanosomes from Lu. nordestina and Lu. trinidadensis. Flagellate infections were recorded in 8 of 21 species examined for the first time, and some were isolated directly from insects into cultures. Le. b. braziliensis was transmitted to a hamster by the bite of a wild-caught, naturally infected Ps. "wellcomei". 7 of the 35 infected Ps. "wellcomei" were allowed to oviposit and the eggs were reared to adults. Four produced Ps. wellcomei males only, confirming the r?le of this species as the major vector of Le. b. braziliensis.     

Influence of rearrangement and cleaning of the peridomiciliary area and building disinsectization on sandfly population density in the municipality of Doutor Camargo, Paraná State, Brazil

Phlebotomine sandfly captures were performed in the domicile, domestic animal shelters, and peridomicile before and after rearrangement, cleaning, and disinsectization. Phlebotomine sandflies were captured with Falc?o traps from October 1998 to April 2000 in the Recanto Marista district, Doutor Camargo municipality, Paraná State. The results were compared with those from October 1996 to September 1997. In this survey, 122,616 phlebotomine sandflies were captured using 10 traps, as compared to 157,983 in the previous period, with 6 traps. Lutzomyia neivai predominated in both periods. During the former period an hourly average of 1,641.9 phlebotomine sandflies were captured as compared to 806.7 in the latter. The results with four traps installed in the same locations shows that the hourly average was 1,318.8 in the former period and 156.0 in the latter. The large reduction in the number of phlebotomine sandflies captured in the second period may be due to the impact of alterations in the environment and the disinsectization of the buildings after the first period.     

Spraying houses in the Peruvian Andes with lambda-cyhalothrin protects residents against cutaneous leishmaniasis

A household vector control trial was carried out in the Peruvian Andes to measure the effect of spraying inside walls and ceilings with lambda-cyhalothrin on the risk for residents of cutaneous leishmaniasis caused by Leishmania peruviana. The mortality rates of Lutzomyia verrucarum measured with WHO contact bioassay cones set on adobe walls characteristic of the endemic region indicated an LD95 for lambda-cyhalothrin of about 20 mg/m2, and no reduction in effectiveness for at least 6 months on indoor adobe walls sprayed with 25 mg/m2. A random selection of 112 houses were sprayed (starting in 1992/93) at 6-monthly intervals with a mean dose of 34 mg/m2, leaving 154 control houses (with closely matched pre-intervention measurements of incidence and sandfly abundance). Comparisons of pre- and post-intervention sandfly indoor abundance, measured at regular intervals for up to 2 years using CDC light traps, in 22 sprayed and 21 control houses demonstrated that spraying significantly reduced the indoor abundance of Lu. verrucarum by an average of 78% and of Lu. (Helcocyrtomyia) peruensis by 83%. Spraying was also associated with a significant reduction of 77% in the proportion of bloodfed sandflies collected in light traps. The proportion of susceptible householders acquiring leishmaniasis during the trial was significantly reduced by 54% as a result of spraying. The observed impact of spraying was greatest, 81% (95% confidence intervals 20-95%), when the cases detected during the first 6 months after the intervention were excluded from the analysis, suggesting a significant pre-patent period.     

中国黑瞎子岛吸血双翅目昆虫调查研究

目的调查黑龙江省抚远县黑瞎子岛吸血双翅目昆虫蚊、蠓、虻的种群构成,主要种群的昼夜数量动态。方法采用人帐诱、诱虫灯诱和网捕法采集蚊、蠓、虻。结果在黑瞎子岛采获蚊、蠓、虻37 272只,经分类鉴定,其中蚊科4属10种,优势种群为刺扰伊蚊(94.68%);蠓科2属5种,优势种为刺螫库蠓(84.69%);虻科5属15种,优势种群为骚扰黄虻(29.84%)和土灰虻(23.90%)。不同月份的蚊种组成有所不同。4种主要蚊种昼夜24h的数量动态观察结果表明,活动时间为刺扰伊蚊24h,叮刺伊蚊在3:00AM~21:00PM,凶小库蚊在6:00AM~20:00PM,中华按蚊在19:00PM~3:00AM;高峰期,刺扰伊蚊在3:00AM和20:00PM出现2次高峰;凶小库蚊在17:00PM,叮刺伊蚊在18:00PM和中华按蚊在21:00PM仅出现1次高峰。6种主要虻种1日活动时间在4:00AM~19:00PM;土灰虻、骚扰黄虻和黑胫黄虻均14:00PM,霍氏黄虻在15:00PM,雁虻在16:00PM,原野虻在18:00PM出现1次高峰。结论此次调查为黑龙江省黑瞎子岛吸血蚊、蠓、虻种群构成、种群动态研究和防治提供了参考依据。     

Findings of Phlebotominae (Diptera: Psychodidae) in the southern coast of the State of S?o Paulo, Brazil

Five species of phlebotomine sandflies were caught on the Southern part of the coast of S. Paulo, Brazil. CDC-light and Shannon traps were used, as well as human-bait, during two investigations into Culicidae mosquitoes. Lutzomyia intermedia and L. flaviscutellata were found among those sandflies. The localities investigated were swampy environments and scant human cases of cutaneous leishmaniasis have been notified there. Both situations suggest the autochthonous nature of the human cases registered there.     

Distribution of species from genus Anopheles (Diptera, Culicidae) in the State of Maranhão, Brazil

We studied the distribution and diversity of Anopheles species in 123 counties (municipalities) in the State of Maranh?o, Brazil. The basic method consisted of capturing female specimens inside and around human dwellings between 6 PM and 6 AM from January 1992 to December 2001. A total of 84,467 specimens belonging to 24 species were captured, with a predominance of A. triannulatus sensu lato (20,788), A. darlingi (19,083), A. nuneztovari (16,884), A. albitarsis s.l. (14,352), A. aquasalis (8.202), and A. evansae (2,885). The other 18 species together accounted for only 2.7% of the total. The species found in the most counties were A. albitarsis s.l. (109 counties), A. triannulatus s.l. (106), A. nuneztovari (93), A. darlingi (87), and A. evansae (64). The richness and wide distribution of anopheline species in Maranh?o agree with the State's geographic position among Brazil's macro-regions, resulting in a mixed fauna with representative elements from these regions.