Acute micro-outbreak of Chagas disease in the southeastern Amazon: a report of five cases.

BACKGROUND: Chagas disease is gaining importance in the Brazilian Amazon region as a differential diagnosis of febrile syndrome. The most recent microoutbreak occurred in Ipixuna, in Amazonas state. METHODS: An epidemiological survey was conducted using parasitological and serological tests, and electrocardiographic analysis. RESULTS: The patients belonged to one family and had ingested açaí acquired from Ipixuna. All patients reported fever and initially a thick blood smear test was done to identify Trypanosoma cruzi. Benznidazole treatment was administered to all patients. CONCLUSIONS: Knowledge of the epidemiological dynamics of Chagas disease allows us to improve control and management measures for this disease.

Acute micro-outbreak of Chagas disease in the southeastern Amazon: a report of five cases

ABSTRACT Background: Chagas disease is gaining importance in the Brazilian Amazon region as a differential diagnosis of febrile syndrome. The most recent microoutbreak occurred in Ipixuna, in Amazonas state. Methods: An epidemiological survey was conducted using parasitological and serological tests, and electrocardiographic analysis. Results: The patients belonged to one family and had ingested açaí acquired from Ipixuna. All patients reported fever and initially a thick blood smear test was done to identify Trypanosoma cruzi. Benznidazole treatment was administered to all patients. Conclusions: Knowledge of the epidemiological dynamics of Chagas disease allows us to improve control and management measures for this disease.

First report of treatment failure in a patient with cutaneous leishmaniasis infected by Leishmania (Viannia) naiffi carrying Leishmania RNA virus: a fortuitous combination?

We report the case of a 32-year-old man from Rio de Janeiro, who was infected in the Amazon region of Brazil by Leishmania (Viannia) naiffi. Generally, patients with L. naiffi cutaneous leishmaniasis exhibit a good therapeutic response to either pentavalent antimonials or pentamidine. However, after pentamidine treatment, this patient's infection evolved to therapeutic failure. To understand this clinical outcome, we investigated the presence of the Leishmania RNA virus (LRV) in parasites isolated from the cutaneous lesion; herein, we discuss the possible association between a poor response to pentamidine therapy and the presence of the LRV.

First report of treatment failure in a patient with cutaneous leishmaniasis infected by Leishmania (Viannia) naiffi carrying Leishmania RNA virus: a fortuitous combination?

Abstract We report the case of a 32-year-old man from Rio de Janeiro, who was infected in the Amazon region of Brazil by Leishmania (Viannia) naiffi. Generally, patients with L. naiffi cutaneous leishmaniasis exhibit a good therapeutic response to either pentavalent antimonials or pentamidine. However, after pentamidine treatment, this patient's infection evolved to therapeutic failure. To understand this clinical outcome, we investigated the presence of the Leishmania RNA virus (LRV) in parasites isolated from the cutaneous lesion; herein, we discuss the possible association between a poor response to pentamidine therapy and the presence of the LRV.

Composition of sand fly fauna (Diptera: Psychodidae) and detection of Leishmania DNA (Kinetoplastida: Trypanosomatidae) in different ecotopes from a rural settlement in the central Amazon, Brazil.

BACKGROUND: Phlebotomine sand flies (Diptera: Psychodidae) are vectors of Leishmania species, the etiological agents of leishmaniasis, which is one of the most important emerging infectious diseases in the Americas. In the state of Amazonas in Brazil, anthropogenic activities encourage the presence of these insects around rural homes. The present study aimed to describe the composition and distribution of sand fly species diversity among the ecotopes (intradomicile, peridomicile and forest) in an area of American cutaneous leishmaniasis transmission and detect natural infection with Leishmania DNA to evaluate which vectors are inside houses and whether the presence of possible vectors represents a hazard of transmission. RESULTS: Phlebotomine sand flies were collected using light traps. A total of 2469 specimens representing 54 species, predominantly females (71.2%), were collected from four sites. Polymerase chain reaction analysis was performed on 670 samples to detect Leishmania DNA. Most of the samples (79.5%) were collected in the forest, with areas closer to rural dwellings yielding a greater abundance of suspected or proven vectors and a larger number of species containing Leishmania DNA. Nyssomyia umbratilis and Bichromomyia flaviscutellata were found near rural homes, and Ny. umbratilis was also found inside homes. Leishmania DNA was detected in different species of sand flies in all ecotopes, including species with no previous record of natural infection. CONCLUSIONS: There is no evidence that vectors of American cutaneous leishmaniasis are becoming established inside homes, but there are sand flies, including Ny. umbratilis and other possible vectors, in environments characterized by a human presence. These species continue to be predominant in the forest but are prevalent in areas closer to ecotopes with a greater human presence. The existence of proven or suspected vectors in this ecotope is due to the structural organization of rural settlements and may represent a hazard of transmission. Although the detection of Leishmania DNA in species that were not previously considered vectors does not mean that they are transmitting the parasite, it does show that the parasite is circulating in ecotopes where these species are found.

Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon.

BACKGROUND: Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU's. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil. METHODS: Blood culture and xenodiagnosis were performed in 36 patients with positive serology for Chagas disease who participated in a serological survey performed in urban and rural areas of Manaus, Amazonas. DNA samples were extracted from the feces of triatomines used for xenodiagnosis, and the nontranscribed spacer of the mini-exon gene and the mitochondrial gene cytochrome oxidase subunit II (COII) were amplified by PCR and sequenced. RESULTS: Blood culture and xenodiagnosis were negative in 100% of samples; however, molecular techniques revealed that in 13 out of 36 (36%) fecal samples from xenodiagnosis, T. cruzi was characterized as the DTU TcI, and different haplotypes were identified within the same DTU. CONCLUSION: The DTU TcI, which is mainly associated with acute cases of Chagas disease in the Amazon region, is also responsible for chronic infection in patients from a region in the State of Amazonas.