Orally-transmitted Chagas disease: Epidemiological, clinical, serological and molecular outcomes of a school microepidemic in Chichiriviche de la Costa, Venezuela

Abstract

Oral transmission of Trypanosoma cruzi is a frequent cause of acute Chagas disease (ChD). In the present cross-sectional study, we report the epidemiological, clinical, serological and molecular outcomes of the second largest outbreak of oral ChD described in the literature. It occurred in March 2009 in Chichiriviche de la Costa, a rural seashore community at the central littoral in Venezuela. The vehicle was an artisanal guava juice prepared at the local school and Panstrongylus geniculatus was the vector involved. TcI genotype was isolated from patients and vector; some showed a mixture of haplotypes. Using molecular markers, parasitic loads were high. Eighty-nine cases were diagnosed, the majority (87.5%) in school children 6-15 years of age. Frequency of symptomatic patients was high (89.9%) with long-standing fever in 87.5%; 82.3% had pericardial effusion detected by echocardiogram and 41% had EKG abnormalities. Three children, a pregnant woman and her stillborn child died (5.6% mortality). The community was addressed by simultaneous determination of specific IgG and IgM, confirmed with indirect hemagglutination and lytic antibodies. Determination of IgG and IgA in saliva had low sensitivity. No individual parasitological or serological technique diagnosed 100% of cases. Culture and PCR detected T. cruzi in 95.5% of examined individuals. Based on the increasing incidence of oral acute cases of ChD, it appears that food is becoming one of the most important modes of transmission in the Amazon, Caribbean and Andes regions of America.

Keywords: Chagas disease; Chichiriviche de la Costa; Foodborne; Oral transmission; Saliva; Venezuela.

Graphical abstract

Fig. 1

Geographical location of Chichiriviche de la Costa, Vargas State in Venezuela. A coastal place hidden in the mountains in the north central littoral of Venezuela.

Fig. 2

Timeline of the onset of fever in oral transmitted Chagas disease patients, Chichiriviche de la Costa, Venezuela, 2009.

Fig. 3

A fatal orally-transmitted Chagas disease case: a pregnant cook lady 24 years old. Noticeable facial edema. X Ray: cardiothoracic relationship > 50% without signs of pulmonary hypertension. Cardiac enlargement due to pericardial effusion. Echosonogram: short axis projection where pericardial effusion and increased left ventricular wall are evidenced by edema.

Fig. 4

Molecular characterization of Trypanosoma cruzi isolates of the outbreak of Chagas disease by oral route occurred in Chichiriviche de la Costa, Venezuela. a) Schematic representation of the amplified products expected for each of the Trypanosoma cruzi DTUs. b) Description of molecular data of the different Chagas disease patients included in this study, and their parasitic loads measured by SatDNA and kDNA qPCR assays. c) Sequence of the SL-IR microsatellite motif and characterization of haplotypes by each isolate of Trypanosoma cruzi from vector and patients. (+): CQ strain (DTU I); (−): CL-Brener strain (DTU VI); ND: Undetermined; NQ: Unquantifiable; nt: nucleotides. SatDNA qPCR limit of quantification (1.53 par.eq./mL); kDNA qPCR limit of quantification (0.90 par.eq./mL).