Human infectiousness and parasite load in chronic patients seropositive for Trypanosoma cruzi in a rural area of the Argentine Chaco.

Human infectiousness and parasite load in chronic patients seropositive for Trypanosoma cruzi in a rural area of the Argentine Chaco. Infect Genet Evol. 2019 Nov 01;:104062 Authors: Macchiaverna NP, Enriquez GF, Bua J, Fernández MP, Sartor PA, Gürtler RE, Cardinal MV Abstract A key parameter in the transmission of vector-borne infections, including Chagas disease, is the ability of the different host species to transmit the parasite to the vector (infectiousness). Here, we determined infectiousness to the vector of Trypanosoma cruzi-seropositive humans examined by artificial xenodiagnosis (XD), established its relationship with T. cruzi DNA levels (a surrogate of intensity of parasitemia) quantified by real-time PCR (qPCR), and assessed whether infectiousness was associated with the body mass index (BMI), age, ethnic background and parasite genotype. XD was performed to 117 T. cruzi-seropositive residents from Pampa del Indio and parasite load was quantified in 81 of them. By optical microscopy (OM) 32.7% of the people were infectious and this fraction doubled (60.5%) when XD triatomines were examined by molecular methods. The mean infectiousness (defined as the percentage of infected triatomines among the total number of insects examined by OM 30 days post-feeding) was 5.2%, and the mean parasite load was 0.51 parasites equivalents per ml. Infectiousness to the vector was associated negatively with age and BMI, and positively ...
Source: Infection, Genetics and Evolution - Category: Genetics & Stem Cells Authors: Tags: Infect Genet Evol Source Type: research