Sandfly frequency in a clean and well-organized rural environment in the state of Paraná, Brazil

INTRODUCTION: Sandflies caught in Santa Juliana Farm in Sarandi, State of Paraná, Brazil, were assessed in terms of their fauna, seasonality, and frequency in the homes and in shelters of domestic animals around the homes, as well as in the nearby forest. METHODS: In Santa Juliana Farm, there are no records of cases of ACL, differing from other relatively clean and organized areas where surveys of sandflies have been conducted in Paraná. Samples were collected with Falcão light traps, fortnightly from 22:00 to 02:00 hours, from November 2007 to November 2008. RESULTS: A total of 4,506 sandflies were captured, representing 13 species, predominantly Nyssomyia whitmani (71.8%). More sandflies were collected in the forest (52.6%) than outside the forest (residences and pigsty) (47.4%). However, Ny. whitmani was collected in greater numbers outside (38.3%) than inside the forest (33.5%). Most sandflies were collected in the warmer months and during periods with regular rainfall. CONCLUSIONS: The results suggest that cleaning and organization around the houses could reduce sandfly population in peridomicile. Constructing shelters for animal at a distance of approximately 100m from domiciles is recommended to prevent the invasion of sandflies, as this farm has an area of preserved forest, with wild animals and sandflies present to maintain the enzootic cycle of Leishmania.

Natural infection of triatomines (Hemiptera: Reduviidae) by trypanosomatids in two different environments in the municipality of Ouro Preto do Oeste, State of Rondônia, Brazil

INTRODUCTION: This study analyzed the occurrence and the contamination of triatomines by trypanosomatids in Orbignya speciosa (babassu) specimens in the State of Rondônia, Brazil, in two different environments (pasture and woods). METHODS: Capture of triatomines on babassus and microscopic search for trypanosomatids in their digestive tube were carried out. RESULTS: Four hundred ninety-four (494) specimens were captured (Rhodnius prolixus and R.robustus), of which 35.6% of the triatomines were positive for trypanosomatids. CONCLUSIONS: The high index of natural infection along with the abundance of triatomines points out to the necessity to create an epidemiological surveillance system to monitor vector-borne transmission and deepen the studies on the ecology of such vectors in the Amazon.

Cutaneous leishmaniasis in northeastern Brazil: a critical appraisal of studies conducted in State of Pernambuco

American cutaneous leishmaniasis (ACL) is a complex disease with clinical and epidemiological features that may vary from region to region. In fact, at least seven different Leishmania species, including Leishmania (Viannia) braziliensis, Leishmania (Viannia) guyanensis, Leishmania (Viannia) lainsoni, Leishmania (Viannia) naiffi, Leishmania (Viannia) shawi, Leishmania (Viannia) lindenbergi, and Leishmania (Leishmania) amazonensis, have been implicated in the etiology of ACL in Brazil, and numerous phlebotomine sandfly species of the genus Lutzomyia have been regarded as putative or proven vectors. Because ACL is a focal disease, understanding the disease dynamics at the local level is essential for the implementation of more effective control measures. The present paper is a narrative review about the ACL epidemiology in Pernambuco, northeastern Brazil. Furthermore, the need for more effective diagnosis, treatment, control and prevention strategies for the affected populations is highlighted. This paper will provide researchers with a critical appraisal of ACL in Pernambuco. Hopefully, it will also be helpful for public health authorities to improve current control strategies against ACL at the state and country levels.

Ecological aspects of the sandfly fauna (Diptera, Psychodidae) in an American cutaneous leishmaniasis endemic area under the influence of hydroelectric plants in Paranapanema river, State of Paraná, Brazil

INTRODUCTION: An epidemiological study was undertaken to identify determinant factors in the occurrence of American cutaneous leishmaniasis in areas under the influence of hydroelectric plants in Paranapanema river, State of Paraná, Brazil. The ecological aspects of the phlebotomine fauna were investigated. METHODS: Sandflies were sampled with automatic light traps from February 2004 to June 2006 at 25 sites in the urban and rural areas of Itambaracá, and in Porto Almeida and São Joaquim do Pontal. RESULTS: A total of 3,187 sandflies of 15 species were captured. Nyssomyia neivai predominated (34.4%), followed by Pintomyia pessoai (32.6%), Migonemyia migonei (11.6%), Nyssomyia whitmani (8.8%), and Pintomyia fischeri (2.7%), all implicated in the transmission of Leishmania. Males predominated for Ny. neivai, and females for the other vector species, with significant statistical differences (p < 0.001). Nyssomyia neivai, Pi. pessoai, Ny. whitmani, Brumptomyia brumpti, Mg. migonei, and Pi. fischeri presented the highest values for the Standardized Species Abundance Index (SSAI). The highest frequencies and diversities were found in the preserved forest in Porto Almeida, followed by forests with degradation in São Joaquim do Pontal and Vila Rural. CONCLUSIONS: Sandflies were captured in all localities, with the five vectors predominating. Ny. neivai had its highest frequencies in nearby peridomestic environments and Pi. pessoai in areas of preserved forests. The highest SSAI values of Ny. neivai and Pi. pessoai reflect their wider dispersion and higher frequencies compared with other species, which seems to indicate that these two species may be transmitting leishmaniasis in the area.

Phlebotomine sandflies fauna (Diptera: Psychodidae) at rural settlements in the municipality of Cáceres, State of Mato Grosso, Brazil

INTRODUCTION: Leishmaniasis is expanding across Brazil, including the State of Mato Grosso (MT). The aim of this study was to characterize the phlebotomine sandfly fauna at threerural settlements located in the municipality of Cáceres, MT, from August 2010 to July 2011. METHODS: Sandfly captures were conducted at the forest border and in intra and peridomicile areas with automatic light traps, biweekly, from 5pm to 6am. RESULTS: Of the 630 sandflies collected, 348 were female, and 282 were male. Captured specimens were distributed across 11 genera - Brumptomyia, Evandromyia, Expapillata, Lutzomyia, Martinsmyia, Micropygomyia, Nyssomyia, Pintomyia, Psathyromyia, Psychodopygus, and Sciopemyia - and 28 species. Among these, six species had not been marked yet in MT (Brumptomyia avellari, Br. mangabeirai, Evandromyia aldafalcaoae, Micropygomyia echinatopharynx, Micropygomyia peresi, and Pa. campograndensis). Nyssomyia whitmani was the most abundant species across ecotopes at all settlements. Interestingly, Lutzomyia longipalpis and Lutzomyia cruzi were found in sympatry. CONCLUSIONS: The disorganized occupation of the environment that is happening at the rural settlements of Mata Comprida, Laranjeira I and II could provide opportunities for the domiciliation of wild populations of phlebotomine, including vectors of leishmaniasis. Therefore, more studies are needed to understand the epidemiology of the disease in these areas and its impact on the human population.

Profile and geographic distribution of reported cases of visceral leishmaniasis in Campo Grande, State of Mato Grosso do Sul, Brazil, from 2002 to 2009

INTRODUCTION: This study sought to describe the profile and geographic distribution of reported cases of visceral leishmaniasis (VL) in the City of Campo Grande, State of Mato Grosso do Sul (MS), Brazil, from 2002 to 2009. METHODS: Human data were collected from the Brazilian National Information System for Notifiable Diseases. Canine cases and entomological data were obtained from the Information Service for Canine Visceral Leishmaniasis Control/Campo Grande, MS. RESULTS: A total of 951 records from 2002 to 2009 were investigated. The number of reported cases of VL in males was significantly higher (p < 0.0001) than that in females. The higher frequency observed among males was associated with age (p < 0.0001), which increased in individuals aged 40 years and older. The overall fatality rate was 7.4%. Entomological surveys conducted in 2006, 2007, and 2009 showed the insect vector Lutzomyia longipalpis to be present in all urban regions of the county. CONCLUSIONS: VL cases in humans and dogs, as well as in vectors, occurs in all urban regions of Campo Grande. Despite not observing tendencies of increase or reduction in the incidence of the disease due to aging, the major incidence in men is higher in those aged 40 years or above.

Ecology of phlebotomines (Diptera, Psychodidae) in rural foci of leishmaniasis in tropical Brazil

INTRODUCTION: This work aimed to study the community structure of sandflies, with regard to the richness, constancy, abundance, and monthly frequency of the species with a focus on the transmission of leishmaniasis. METHODS: The study was conducted in the rural villages of Bom Jardim and Santa Maria, situated on the edge of a tropical rain forest in the municipality of São Jose de Ribamar, Maranhão, Brazil. The phlebotomines were captured in the intradomiciles and peridomiciles of each village, with Centers for Disease Control (CDC) light traps set in 10 homes in each village, for 1 year, once a month, from 18h to 6h. RESULTS: We collected 1,378 individuals of 16 sandfly species. The capture success rate was higher in Bom Jardim (0.61 specimens/hour/trap) than that of Santa Maria (0.35/specimens/hour/trap). The sandflies were more abundant in the peridomiciles (86.1%) and in the rainy season (77%). Five species were considered constants (occurring in more than 50% of samples), 5 accessory (25%-50%), and 6 accidental (<25%). The most abundant species were Lutzomyia longipalpis (59.7%) and L whitmani (28%). The permutation analysis showed differences between the species composition of the villages and no separation between the intradomicile and peridomicile of each village. The species that most contributed to the dissimilarity between the light traps of the 2 villages were L. longipalpis, L. whitmani, and L. evandroi, contributing to 80.8% of the variation among groups. CONCLUSIONS: The high level of richness and abundance of species and the presence of competent vectors throughout the year and around houses justify the occurrence of leishmaniasis cases reported in the area.

Epidemiological aspects of American cutaneous leishmaniasis and phlebotomine sandfly population, in the municipality of Monte Negro, State of Rondônia, Brazil

Introduction: This work was carried out on the purpose of identifying the species of phlebotomine sandflies in the municipality of Monte Negro, state of Rondonia, Brazil, that may have been transmitting the American cutaneous leishmaniasis (ACL), and concisely describe epidemiological aspects of disease. METHODS: The epidemiologic and socioeconomical indicators were obtained from government institutions and the local Municipal Secretary of Health. Phlebotomine sandflies were captured using CDC light traps between July 2006 to July 2008. The total of 1,240 of female sandflies were examined by PCR method directed to k-DNA. RESULTS: There has been a significant decrease in the incidence of ACL of about 50% over the last ten years in the municipality. A total of 1,935 specimens of 53 sandfly species were captured, three of the genus Brumptomyia genus and 50 of the genus Lutzomyia. The predominant species was Lutzomyia acanthopharynx, Lutzomyia whitmani, Lutzomyia geniculata and Lutzomyia davisi. None were positive for Leishmania sp. CONCLUSIONS: Four sandflies species were found in the State of Rondonia for the first time: Brumptomyia brumpti, Lutzomyia tarapacaensis, Lutzomyia melloi and Lutzomyia lenti. The presence of Lutzomyia longipalpis, was also captured. Socioeconomical improvement of Brazilian economy and the increase of environmental surveillance in the last 15 years collaborated in the decrease of people exposed to vectors, reducing the incidence of ACL.

Survey of Bancroftian filariasis infection in humans and Culex mosquitoes in the western Brazilian Amazon region: implications for transmission and control

IntroductionThe aim of this work was to identify possible lymphatic filariasis foci in the western Brazilian Amazonian that could be established from the reports of Rachou in the 1950s. The study was conducted in three cities of the western Brazilian Amazon region - Porto Velho and Guajará-Mirim (State of Rondônia) and Humaitá (State of Amazonas).MethodsFor human infection evaluation thick blood smear stained with Giemsa was used to analyze samples collected from 10pm to 1am. Polymerase chain reaction (PCR) was used to examine mosquito vectors for the presence of Wuchereria bancrofti DNA. Humans were randomly sampled from night schools students and from inhabitants in neighborhoods lacking sanitation. Mosquitoes were collected from residences only.ResultsA total 2,709 night students enrolled in the Program for Education of Young Adults (EJA), and 935 people registered in the residences near the schools were examined, being 641 from Porto Velho, 214 from Guajará-Mirim and 80 from Humaitá. No individual examined was positive for the presence of microfilariae in the blood stream. A total of 7,860 female Culex quinquefasciatus specimens examined were negative by PCR.ConclusionsThis survey including human and mosquito examinations indicates that the western Amazon region of Brazil is not a focus of Bancroftian filariasis infection or transmission. Therefore, there is no need to be included in the Brazilian lymphatic filariasis control program.

Historical analysis of the records of sylvan yellow fever in the State of Amazonas, Brazil, from 1996 to 2009

IntroductionYellow fever is a non-contagious infectious disease, highly lethal, transmitted by the Aedes, Haemagogus and Sabethes.MethodsDescriptive retrospective study of the yellow fever cases in Amazonas, between 1996 and 2009.ResultsForty two cases of yellow fever were confirmed, with 30 deaths, 10% of which were foreigners.ConclusionsThe presence of Aedes aegypti and Aedes albopictus in both rural Amazonas and its capital demonstrates the dispersion of these vectors and underscores the need for better and continuous epidemiological and entomological control.

Non-biting flying insects as carriers of pathogenic bacteria in a Brazilian hospital

IntroductionInsects have been described as mechanical vectors of nosocomial infections.MethodsNon-biting flying insects were collected inside a pediatric ward and neonatal-intensive care unit (ICU) of a Brazilian tertiary hospital.ResultsMost (86.4%) of them were found to carry one or more species of bacteria on their external surfaces. The bacteria isolated were Gram-positive bacilli (68.2%) or cocci (40.9%), and Gram-negative bacilli (18.2%).ConclusionsInsects collected inside a hospital were carrying pathogenic bacteria; therefore, one must consider the possibility they may act as mechanical vectors of infections, in especially for debilitated or immune-compromised patients in the hospital environments where the insects were collected.

Approaches towards tick and tick-borne diseases control

Ticks are obligate haematophagous ectoparasites of wild and domestic animals as well as humans, considered to be second worldwide to mosquitoes as vectors of human diseases. Tick-borne diseases are responsible worldwide for great economic losses in terms of mortality and morbidity of livestock animals. This review concerns to the different tick and tick-parasites control methods having a major focus on vaccines. Control of tick infestations has been mainly based on the use of acaricides, a control measure with serious drawbacks, as responsible for the contamination of milk and meat products, as a selective factor for acaricide-resistant ticks and as an environmental contaminant. Research on alternatives to the use of acaricides is strongly represented by tick vaccines considered a more cost-effective and environmentally safe strategy. Vaccines based on the Bm86 tick antigen were used in the first commercially available cattle tick vaccines and showed good results in reducing tick numbers, affecting weight and reproductive performance of female ticks which resulted in reduction of cattle tick populations over time and consequently lower reduction of the pathogen agents they carry.

Larvicidal effects of endophytic and basidiomycete fungus extracts on Aedes and Anopheles larvae (Diptera, Culicidae)

Introduction In vitro bioassays were performed to access the larvicidal activity of crude extracts from the endophytic fungus Pestalotiopsis virgulata (Melanconiales, Amphisphaeriaceae) and the saprophytic fungus Pycnoporus sanguineus (Basidiomycetes, Polyporaceae) against the mosquitoes Aedes aegypti and Anopheles nuneztovari. Methods The extracts were tested at concentrations of 100, 200, 300, 400 and 500ppm. Ethyl acetate mycelia (EAM) extracts and liquid culture media (LCM) from Pe. virgulata and Py. sanguineus were tested against third instar larvae of Ae. aegypti and An. nuneztovari. Results The larvicidal activity of the EAM extracts from Pe. virgulata against Ae. aegypti had an LC50=101.8ppm, and the extract from the basidiomycete fungus Py. sanguineus had an LC50=156.8ppm against the Ae. aegypti larvae. The Pe. virgulata extract had an LC50=16.3ppm against the An. nuneztovari larvae, and the Py. sanguineus extract had an LC50=87.2ppm against these larvae. Conclusions These results highlight the larvicidal effect of EAM extracts from the endophyte Pe. virgulata against the two larval mosquitoes tested. Thus, Pe. virgulata and Py. sanguineus have the potential for the production of bioactive substances against larvae of these two tropical disease vectors, with An. nuneztovari being more susceptible to these extracts.

Blood feeding patterns of Nyssomyia intermedia and Nyssomyia neivai (Diptera, Psychodidae) in a cutaneous leishmaniasis endemic area of the Ribeira Valley, State of São Paulo, Brazil

Introduction The aim of this study was to identify the blood feeding sources of Nyssomyia intermedia (Ny. intermedia) and Nyssomyia neivai (Ny. neivai), which are Leishmania vectors and the predominant sandfly species in the Ribeira Valley, State of São Paulo, Brazil, an endemic area for cutaneous leishmaniasis. Methods Specimens were captured monthly between February 2001 and December 2003 on a smallholding and a small farm situated in the Serra district in the Iporanga municipality. The blood meals of 988 engorged females were tested using the avidin-biotin immunoenzymatic enzyme-linked immunosorbent assay (ELISA). Seven blood meal sources were investigated: human, dog, chicken, bovine, pig, horse and rat. Results The results showed that among the females that fed on one or more blood sources, the respective percentages for Ny. intermedia and Ny. neivai, respectively, were as follows: human (23% and 36.8%), pig (47.4% and 26.4%), chicken (25.7% and 36.8%) and dog (3.9% and 0%), and the differences in the blood sources between the two species were statistically significant (p = 0.043). Conclusions Both species had predominant reactivity for one or two blood sources, and few showed reactivity indicating three or four sources. Many different combinations were observed among the females that showed reactivity for more than one source, which indicated their opportunistic habits and eclecticism regarding anthropic environmental conditions.

Susceptibility of Argentinean Biomphalaria tenagophila and Biomphalaria straminea to infection by Schistosoma mansoni and the possibility of geographic expansion of mansoni schistosomiasis

Introduction Human migration and the presence of natural vectors (mollusks) of Schistosoma mansoni are the primary causes of the expansion of mansoni schistosomiasis into southern areas of South America. Water conditions are favorable for the expansion of this disease because of the extensive hydrographic network, which includes the basins of the Paraná and Uruguay rivers and favors mollusk reproduction. These rivers also aid agriculture and tourism in the area. Despite these favorable conditions, natural infection by S. mansoni has not yet been reported in Argentina, Uruguay, or Paraguay. Methods Two species of planorbid from Argentina, Biomphalaria straminea and B. tenagophila, were exposed to the miracidia of five Brazilian strains of S. mansoni. Results Biomphalaria tenagophila (Atalaya, Buenos Aires province) was infected with the SJS strain (infection rate 3.3%), confirming the experimental susceptibility of this Argentinian species. Biomphalaria straminea (Rio Santa Lucía, Corrientes province) was susceptible to two Brazilian strains: SJS (infection rate 6.7%) and Sergipe (infection rate 6.7%). Conclusions These results demonstrate that species from Argentina have the potential to be natural hosts of S. mansoni and that the appearance of foci of mansoni schistosomiasis in Argentina is possible.