Assessing reservoir host status in leishmaniasis with special reference to the infectiousness of Leishmania (Viannia) braziliensis infections in wild rodents

ABSTRACT Molecular methods have been responsible for a notable increase in the detection of Leishmaniinae infections in wild animals. Determining their infectiousness is of paramount importance in evaluating their epidemiological significance. One of the most efficient ways of determining infectiousness for vector borne diseases is xenodiagnosis with the appropriate vector. However, this is logistically very difficult to accomplish in the field, and an ideal solution is to find a molecular surrogate for xenodiagnosis. In this review we discuss different approaches to the problem by focusing on the infectiousness of Leishmania (Viannia) braziliensis in rodents under laboratory and field conditions. Comparisons with similar studies for other Leishmania species emphasizes that there are pivotal differences in the infectiousness and the importance of asymptomatic infections in different hosts. Potentially the most promising surrogate is the real time quantitative PCR (qPCR). However, its success depends on choosing a tissue that relates to the vector's feeding location and the parasite's tissue tropism. This requires detailed knowledge of the infection of each species in its wild hosts. We conclude that for L. (V.) braziliensis infections in wild rodents the tissue of choice for a molecular xenodiagnostic test, based on the qPCR is blood, providing that a significant number of samples must be examined.

Should reproductively isolated populations of Lutzomyia longipalpis sensu lato receive taxonomically valid names?

A group of 18 research workers involved in different aspects of the biology of Lutzomyia longipalpis discussed whether or not it is important to give taxonomically valid names to populations that have been defined by biological, biochemical and molecular methods to be reproductively isolated. The type material of this medically important species has been lost and because of this it was recommended that a colony should be established from insects captured in the region of the type area and that their description should serve as the basis for future descriptions. It was pointed out that there is a lack of uniformity in the naming of closely related American sand flies and that some of the differences between populations of Lu. longipalpis are greater than those between accepted species. The majority of the participants agreed that the populations that have been defined in the literature as sibling species should be named.

Ectoparasite infestation on rural dogs in the municipality of São Vicente Férrer, Pernambuco, Northeastern Brazil / Infestação por ectoparasitos em cães rurais no município de São Vicente Férrer, Pernambuco, Nordeste do Brasil

This article presents the results of a study on ectoparasites infesting rural dogs in Pernambuco, northeastern Brazil. Forty-one dogs from a rural community of Pernambuco were examined and 70.7 percent were infested by ectoparasites. The prevalence rates of infestation by ticks, fleas, and lice were 58.5, 43.9 and 22 percent, respectively. Of 24 dogs parasitized by ticks, 15 were exclusively infested by Rhipicephalus sanguineus (Latreille) (32 females, 66 males, 9 nymphs; prevalence, 48.8 percent; mean intensity, 5.4), four by Amblyomma ovale Koch (33 females, 19 males; prevalence, 22 percent; mean intensity, 5.8), and five were coinfested by both species. Ctenocephalides felis felis (Bouché) (25 females, 8 males; prevalence, 43.9 percent; mean intensity, 1.9) and Heterodoxus spiniger (Enderlein) (16 females, 11 males, 10 nymphs; prevalence, 22 percent; mean intensity, 4.1) were the only species of flea and louse identified. Tick infestation was more frequent than flea or lice infestations (p < 0.05). No statistical difference was found by sex and age group of the dogs studied and prevalence of infestation. Overall, 48.8 percent (20/41) of the dogs were infested by more than one ectoparasite species.

O presente artigo apresenta os resultados de um estudo sobre os ectoparasitos que infestam cães rurais em Pernambuco, Nordeste do Brasil. Quarenta e um cães de uma comunidade rural de Pernambuco foram examinados e 70,7 por cento estavam infestados por ectoparasitos. As taxas de prevalência de infestação por carrapatos, pulgas e piolhos foram 58,5, 43,9 e 22 por cento, respectivamente. Dos 24 cães parasitados por carrapatos, 15 estavam exclusivamente infestados por Rhipicephalus sanguineus (Latreille) (32 fêmeas, 66 machos, 9 ninfas; prevalência, 48,8 por cento; intensidade média, 5,4), quatro por Amblyomma ovale Koch (33 fêmeas, 19 machos; prevalência, 22 por cento; intensidade média, 5,8), e cinco estavam co-infestados por ambas as espécies. Ctenocephalides felis felis (Bouché) (25 fêmeas, 8 machos; prevalência, 43,9 por cento; intensidade média, 1,9) e Heterodoxus spiniger (Enderlein) (16 fêmeas, 11 machos, 10 ninfas; prevalência, 22 por cento; intensidade média, 4,1) foram as únicas espécies de pulga e piolho identificadas. A infestação por carrapatos foi mais frequente que as infestações por pulgas ou piolhos (p < 0.05). Não houve diferença estatística em relação ao sexo e grupo etário dos cães e a prevalência de infestação. No geral, 48,8 por cento (20/41) dos cães estavam infestados por mais de uma espécie de ectoparasito.

Expansão geográfica da leishmaniose visceral no Estado de Pernambuco / Geographical expansion of visceral leishmaniasis in the State of Pernambuco

Este estudo visa demonstrar a expansão geográfica da leishmaniose visceral no Estado de Pernambuco, Brasil. A partir do número de casos notificados de 1990 a 2001, foram elaborados mapas temáticos sobre a evolução bi-anual da distribuição geográfica da leishmaniose visceral por município. Por fim, foi construído um mapa da distribuição cumulativa dos casos resgistrados durante o período estudado. De 1990 a 2001, foram notificados 1.737 casos de leishmaniose visceral em Pernambuco. Em 1990, apenas 15,2 por cento (n = 28) dos municípios haviam registrado casos, enquanto, após pouco mais de uma década, esse percentual elevou-se para 78,3 por cento (n = 144). A distribuição geográfica cumulativa demonstra uma clara concentração de casos no Agreste e no Sertão. Houve uma considerável expansão geográfica da leishmaniose visceral em Pernambuco, refletindo, provavelmente, o baixo impacto das atuais medidas de controle e é possível que se deva também à melhoria do sistema de notificação.

This study aimed to demonstrate the geographical expansion of visceral leishmaniasis in Pernambuco State, Brazil. With data on the number of visceral leishmaniasis cases notified from 1990 to 2001, maps showing the biannual evolution of the geographical distribution of the disease per municipality were elaborated. A map of the cumulative geographical distribution of the cases registered during the whole period was also constructed. From 1990 to 2001, 1,737 cases of visceral leishmaniasis were notified in Pernambuco. In 1990, 15.2 percent (n = 28) of the municipalities notified cases of the disease. In contrast, this percentage increased to 78.3 percent (n = 144), over an eleven-year period. The map of cumulative geographical distribution during the whole period shows a notable concentration of cases in Agreste and Sertão. A notable geographical expansion of visceral leishmaniasis in Pernambuco also occurred, probably reflecting the low impact of the current control measures and, possibly, an improvement in the notification system.

Leishmaniose tegumentar americana causada por Leishmania (Viannia) braziliensis, em área de treinamento militar na Zona da Mata de Pernambuco / American tegumentary leishmaniasis caused by Leishmania (Viannia) braziliensis in military training area of Zona da Mata in Pernambuco

Este estudo tem como objetivo geral caracterizar a epidemiologia da leishmaniose tegumentar americana em unidade de treinamento militar, localizada no Estado de Pernambuco. Entre 2002 e 2003, vinte e três casos foram diagnosticados através de exame clínico, detecção do parasita e teste de intradermoarreação de Montenegro. Sete amostras de Leishmania (Viannia) braziliensis foram isoladas destes pacientes, identificadas através de reações com anticorpos monoclonais específicos e perfil eletroforético com isoenzimas. Um inquérito epidemiológico de prevalência da infecção por IDRM foi realizado na população que realizou treinamento neste período, no qual foi identificada uma prevalência de 25,3 por cento de infecção. Os dados obtidos, associados com achados prévios nesta área, apresentam evidências da manutenção de um ciclo enzoótico, com a ocorrência de surtos periódicos de leishmaniose tegumentar americana posteriormente à realização de treinamentos nas áreas de floresta Atlântica remanescente.

Lutzomyia naftalekatzi, a new species of phlebotomine sand fly (Diptera: Psychodidae) from Zona da Mata region, Pernambuco, Brazil

Lutzomyia naftalekatzi, a new phlebotomine sand fly belonging to the L. aragaoi species group, is described from specimens collected in Zona da Mata region of Pernambuco, Brazil

American cutaneous leishmaniasis in Pernambuco, Brazil: eco-epidemiological aspects in "Zona da Mata" region

American cutaneous leishmaniasis (ACL) has been increasing in Pernambuco, thus becoming an important problem for Public Health. The incindence is predominant in the region called "Zona da Mata", in the east of this state. This region corresponds geographically to the primitive area of the Atlantic forest. In order to characterize the eco-epidemiology expression of ACL in this region, two localities situated in the municipalities of Amaraji e Cortes have been selected by the criterion of higher incindence of human cases. Five stocks of patients were characterized and identified on the basis of enzyme profiles as a new variant of Leishmania (V.) braziliensis. A survey of wild and domestic animals was carried out by means of a parasitological and serological diagnosis. Through the analysis of the spleen and liver imprints, were detected amastigotes compatible with Leishmania in five Nectomys s. squamipes, five Bolomys l. pixuna, two Rattus r. alexandrinus and one Rattus r. frugivorus. For two years we carried out monthly sandflies captures using CDC light traps as well as manual captures. Lutzomyia whitmani was predominant, which accounted for 97.4 por cento of the total. These data indicate a strong evidence on the vector and the potential reservoirs of L. braziliensis in this region.