Characterisation of an area of coexistent visceral and cutaneous leishmaniasis transmission in the State of Piauí, Brazil.

BACKGROUND: In Brazil, transmission of visceral and cutaneous leishmaniasis has expanded geographically over the last decades, with both clinical forms occurring simultaneously in the same area. OBJECTIVES: This study characterised the clinical, spatial, and temporal distribution, and performed entomological surveillance and natural infection analysis of a leishmaniasis-endemic area. METHODS: In order to characterise the risk of leishmaniasis transmission in Altos, Piauí, we described the clinical and socio-demographic variables and the spatial and temporal distribution of cases of American visceral leishmaniasis (AVL) and American cutaneous leishmaniasis (ACL) cases and identified potential phlebotomine vectors. FINDINGS: The urban area concentrated almost 54% of ACL and 86.8% of AVL cases. The temporal and spatial distribution of AVL and ACL cases in Altos show a reduction in the number of risk areas, but the presence of permanent disease transmission foci is observed especially in the urban area. 3,808 phlebotomine specimens were captured, with Lutzomyia longipalpis as the most frequent species (98.45%). Of the 35 females assessed for natural infection, one specimen of Lu. longipalpis tested positive for the presence of Leishmania infantum and Leishmania braziliensis DNA. MAIN CONCLUSION: Our results indicate the presence of risk areas for ACL and AVL in the municipality of Altos and highlight the importance of entomological surveillance to further understand a possible role of Lu. longipalpis in ACL transmission.

Development of Immunological Assays Based on Leishmania donovani Antigen for Diagnosis of Canine Visceral Leishmaniasis and Their Multicenter Evaluation in Brazil and Italy.

Canine visceral leishmaniasis (CVL) due to Leishmania infantum infection is a zoonotic disease prevalent in the areas of South America and the Mediterranean. Infected dogs as reservoirs can contribute to disease transmission and can be a scourge to public health. Therefore, early diagnosis of infected dogs may play a pivotal role in circumscribing disease progression. Invasive tissue aspiration and insufficient serological methods impair a single assay for prompt CVL diagnosis. In the present study, we aimed to evaluate the potential of Leishmania donovani isolated membrane protein, LAg, for the diagnosis of CVL through immunological assays. Initially, enzyme-linked immunosorbent assay was done with Brazilian dog sera to evaluate the performance of LAg in diagnosing CVL and found sensitivity and specificity of 92.50% and 95%, respectively. The study further confirmed the diagnostic efficacy of LAg in a dipstick format. The dipstick test of canine sera from three centers in Brazil and one center in Italy collectively showed sensitivity values in the range of 53.33% to 100% in recognizing symptomatic dogs and specificity values between 75% and 100% to rule out healthy dogs. Moreover, a rapid immunochromatographic test was developed and optimized using LAg. This test was able to identify 94.73% of CVL of Brazilian origin with specificity of 97.29%. The current results highlight the reactive potential of the L. donovani antigen, LAg, for L. infantum CVL diagnosis and support our previous findings, which suggest the utility of LAg for the diagnosis of both L. donovani and L. infantum human VL in a variety of endemic regions. LAg as a diagnostic candidate may be employed to identify comprehensive CVL cases in epidemiological areas.

Characterisation of an area of coexistent visceral and cutaneous leishmaniasis transmission in the State of Piauí, Brazil

BACKGROUND In Brazil, transmission of visceral and cutaneous leishmaniasis has expanded geographically over the last decades, with both clinical forms occurring simultaneously in the same area. OBJECTIVES This study characterised the clinical, spatial, and temporal distribution, and performed entomological surveillance and natural infection analysis of a leishmaniasis-endemic area. METHODS In order to characterise the risk of leishmaniasis transmission in Altos, Piauí, we described the clinical and socio-demographic variables and the spatial and temporal distribution of cases of American visceral leishmaniasis (AVL) and American cutaneous leishmaniasis (ACL) cases and identified potential phlebotomine vectors. FINDINGS The urban area concentrated almost 54% of ACL and 86.8% of AVL cases. The temporal and spatial distribution of AVL and ACL cases in Altos show a reduction in the number of risk areas, but the presence of permanent disease transmission foci is observed especially in the urban area. 3,808 phlebotomine specimens were captured, with Lutzomyia longipalpis as the most frequent species (98.45%). Of the 35 females assessed for natural infection, one specimen of Lu. longipalpis tested positive for the presence of Leishmania infantum and Leishmania braziliensis DNA. MAIN CONCLUSION Our results indicate the presence of risk areas for ACL and AVL in the municipality of Altos and highlight the importance of entomological surveillance to further understand a possible role of Lu. longipalpis in ACL transmission.

[Natural infection of Lutzomyia longipalpis by Leishmania sp. in Teresina, Piauí State, Brazil]. / Infecção natural de Lutzomyia longipalpis por Leishmania sp. em Teresina, Piauí, Brasil.

In Brazil, control of the vector Lutzomyia longipalpis is one of the main strategies used to limit the expansion of American visceral leishmaniasis. However, studies on the ecology of this sand fly are rare, especially regarding its natural infection with species of Leishmania. A study of the natural infection of Lu. longipalpis by Leishmania sp. was carried out in the Bela Vista neighborhood in the city of Teresina, Piauí State, Brazil, an important area of American visceral leishmaniasis transmission. From February 2004 to January 2005, sand flies were captured with CDC light traps. Approximately 10 female sand flies in each capture were dissected and examined for the presence of evolutionary forms of Leishmania sp. Two sand fly species were identified: 1,832 were Lu. longipalpis and six Lu. whitmani. Twenty female sand flies (1.1%), all Lu. longipalpis, were infected with procyclic and nectomonad forms of Leishmania sp., found mostly in the hindgut. Higher proportions of infected sand flies were found four months after the rainy season, suggesting that environmental factors may predict not only vector abundance (as already known) but also their level of infection.

Occurrence of Lutzomyia longipalpis Lutz & Neiva 1912 and Cerdocyon thous Linnaeus 1977, in a visceral leishmaniasis endemic area in Brazil.

Cerdocyon thous presents a wide geographic distribution in Brazil and its role as a possible Leishmania infantum reservoir in a visceral leishmaniasis (VL) transmission cycle regardless of dogs (Canis familiaris) has been discussed. From this perspective, this work describes the occurrence and use of the habitat by Cerdocyon thous in a Lutzomyia longipalpis occurrence area Teresina (Piaui - Brazil), VL endemic region. Three specimens of C. thous were monitored with the use of radio telemetry and trails and footprints, seeking to find possible natural dens in order to collect the sanflies from the site. Luminous CDC and Damasceno traps were simultaneously installed at the visited sites, where two specimens of L. longipalpis and one L. termitophila were captured. The identification of the dens and trails, allows us to infer that the dens are not used only by the C. thous. Finding the VL vector in natural C. thous natural dens, reinforces the hypothesis of transmission of Le. infantum in the outskirts of the large urban centers, in a cycle that independs from dogs.

Gallic and ellagic acids: two natural immunomodulator compounds solve infection of macrophages by Leishmania major.

Leishmaniasis is a complex of parasitic protozoan diseases caused by more than 20 different species of parasites from Leishmania genus. Conventional treatments are high costly, and promote a sort of side effects. Besides, protozoan resistance to treatments has been reported. Natural products have been investigated as a source of new therapeutic alternatives, not only acting directly against the parasite but also being able to synergistically act on the host immune system in order to control parasitemia. Gallic acid (GA) and ellagic acid (EA) are plant-derived phenolic compounds which are able to induce antiinflammatory, gastroprotective, and anticarcinogenic activities. Therefore, the antileishmania, cytotoxic, and immunomodulatory activities of GA and EA were evaluated in this study. Both GA and EA were able to inhibit the growth of Leishmania major promastigotes (effective concentration (EC50) values 16.4 and 9.8 µg/mL, respectively). The cytotoxicity against BALB/c murine macrophages for GA and EA was also assessed (CC50 values 126.6 and 23.8 µg/mL, respectively). Interestingly, GA and EA also significantly reduced the infection and infectivity of macrophages infected by L. major (EC50 values 5.0 and 0.9 µg/mL, respectively), with selectivity index higher than 20. Furthermore, both GA and EA induced high immunomodulatory activity evidenced by the increase of phagocytic capability, lysosomal volume, nitrite release, and intracellular calcium [Ca2+i] in macrophages. Further investigations are reinforced in order to evaluate the therapeutic effects of GA and EA in in vivo experimental infection model of leishmaniasis.

Leishmania (infantum) chagasi in canine urinary sediment.

Canine visceral leishmaniasis (CVL) is difficult to diagnosis, mainly due to the presence of asymptomatic animals, the diversity of clinical symptoms and the difficulty in obtaining diagnostic evidence of high sensitivity and specificity. The purpose of this study was to diagnose CVL in urinary sediment of 70 dogs of different breeds, sexes and ages from the veterinary hospital of the Federal University of Piauí and Zoonosis Control Center of Teresina, Brazil. The serological tests were TR DPP® for CVL and enzyme-linked immunosorbent assay (ELISA) for CVL, parasitological exams of bone marrow and lymph nodes and urine sediment cultures. Leishmania was detected in the bone marrow and/or lymph node of 61.0% of the animals (43/70), and urine sediment culture was positive in 9.30% (4/43) of these animals. In the serological exams, 70.0% (49/70) were reactive using the DPP and 78.2% (55/70) were reactive using ELISA. The goal of this study was to diagnose the presence of L. (infantum) chagasi in a culture of urinary sediment.

Canine visceral leishmaniasis in Teresina, Brazil: Relationship between clinical features and infectivity for sand flies.

Leishmania chagasi is an intracellular parasite transmitted by the bite of the phlebotomine sand fly Lutzomyia longipalpis, which is the most important of American visceral leishmaniasis. In the gut of the vector, amastigoste forms of the parasite transform into metacyclic promastigotes, from there to the foregut, where they could be transmitted in the next blood meal. Xenodiagnosis is an important tool for the detection of Leishmania, especially when associated to molecular techniques, both being useful for the monitoring and evaluation of dog infectivity in endemic areas. In this study, direct search of Leishmania from material obtained through xenodiagnosis performed in dogs captured in Teresina (Piauí State, Brazil) identified that the predominant forms of the parasite were the procyclic and metacyclic forms located in the hindgut, detected between the 5th and 6th day after the blood meal. Using polymerase chain reaction (PCR), we revealed that dogs with different clinical status were able to infect phlebotomines, the rates of sand fly infection being higher for symptomatic dogs (13%) as compared to asymptomatic ones (3.5%). The direct search was able to demonstrate infection only in phlebotomines in which the blood meal was performed on symptomatic dogs, with a rate of infection of 1.6%. The results underline the importance of using PCR and xenodiagnosis for the detection of Leishmania sp. And for the evaluation of infectivity of dogs in endemic areas, especially those that are asymptomatic.

Heterogeneity of Leishmania infantum chagasi kinetoplast DNA in Teresina (Brazil).

Leishmania infantum chagasi is the causative agent of visceral leishmaniasis in Brazil. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of kinetoplast DNA (kDNA) minicircles was used to evaluate genetic profiles of 48 Leishmania infantum chagasi strains from dog and human parasite cultures, fresh collected dog bone marrow aspirates, and from infected sand flies. Results revealed that heterogeneity in kDNA minicircles depends mostly on the source of the samples, with cultured parasites showing a high degree of homogeneity.