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.

Ornithodoros guaporensis (Acari, Ixodida: Argasidae), a new tick species from the Guaporé River Basin in the Bolivian Amazon

The soft tick Ornithodoros guaporensis n. sp. (Acari: Ixodida: Argasidae) is described from larvae and adults. Morphological analysis and 16S rDNA sequences are provided. Adults were collected from a rocky fissure inhabited by bats located in the Amazonian forest in north-eastern Bolivia (Beni Department) close to the Guaporé River. Larvae were obtained from eggs laid by females collected in the field, and which were fed on rabbits in the laboratory. Larvae of O. guaporensis are morphologically closely related to Ornithodoros rioplatensis, Ornithodoros puertoricensis and Orni-thodoros talaje. Larvae of O. guaporensis and O. rioplatensis can be separated from O. puertoricensis and O. talaje by the number of pairs of dorsal setae (20 in O. guaporensis and O. rioplatensis, 18 in O. puertoricensis and 17 in O. talaje). Larvae of O. guaporensis and O. rioplatensis can be differentiated by the medial dental formula (2/2 in O. guaporensis and 3/3 in O. rioplatensis) and the apex of the hypostome, which is more pointed in O. rioplatensis than in O. guaporensis. The Principal Component Analysis performed with morphometric characters of larvae showed a clear separation among O. guaporensis, O. rioplatensis, O. puertoricensis and O. talaje. Significant morphological differences among adults of these four species were not found. The analysis of the 16S rDNA sequences allowed for the differentiation between O. guaporensis and the remaining Neotropical species of the family Argasidae.

Ornithodoros peropteryx (Acari Argasidae) in Bolivia an argasid tick with a single nymphal stage

By the end of the 1960s, the argasid tick Ornithodoros peropteryx was described from larval specimens collected from the bat Peropteryx macrotis in Colombia. Since its original description, no additional record of O. peropteryx has been reported, and its post-larval stages have remained unknown. During July 2010, 18 larvae were collected from 9 bats (Centronycteris maximiliani), resulting in a mean infestation of 2.0 ± 2.2 ticks per bat (range 1–8). These bats were captured in a farm in northeastern Bolivia close to Guapore´ River in the border with Brazil. Morphological examinations of the larvae revealed them to represent the species O. peropteryx. One engorged larva that was kept alive in the laboratory moulted to a nymph after 9 days. Fourteen days after the larval moulting, the nymph moulted to an adult female without taking any blood meal during the nymphal period. This adult female was used for a morphological description of the female stage of O. peropteryx. In addition, the larvae were used for a morphological redescription of this stage. One larva and two legs extirpated from the adult female were submitted to DNA extraction and PCR targeting a fragment of the mitochondrial 16S rDNA gene, which yielded DNA sequences at least 11 % divergent from any available argasid sequence in Genbank. We show that O. peropteryx ontogeny is characterized by a single, non-feeding, nymphal stage. This condition has never been reported for ticks.

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

Introduction: The 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). Methods: For 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. Results: A 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. Conclusions: This 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.

Survey of hearing disorders in an urban population in Rondonia, Northern Brazil

OBJECTIVE: To identify the prevalence of hearing loss for the population in the urban area. METHODS: A cross-sectional household survey based on the World Health Organization Ear and Hearing Disorders Survey Protocol was conducted in 298 households in the urban area of Monte Negro, Rondonia, Northern Brazil, from 2005 to 2007. Ear examinations, behavioral audiometry and pure tone audiometry were conducted on 577 individuals. RESULTS: The results showed that 3.8% (95%CI 2.17;5.45) of population were classifi ed in the disabling hearing impairment category. The prevalence of moderate hearing impairment was 3.4%; severe impairment was 0.4%; and profound hearing impairment was not found. CONCLUSIONS: The impairing hearing loss prevalence found in this study is within of the international prevalence for this level of hearing loss and smaller than observed in a previous study in the South region of Brazil.