Association between nutritional indicators and infectivity of dogs seroreactive for Trypanosoma cruzi in a rural area of northwestern Argentina

Abstract

The association between the nutritional state of mongrel dogs naturally infected with Trypanosoma cruzi and their infectivity to Triatoma infestans bugs and immune response to Trypanosoma cruzi were studied in the rural village of Amamá, northwestern Argentina. All of the 97 evaluated dogs were classified into one of three categories of external clinical aspect (ECA) based on the degree of muscle development, external evidence of bone structures, state of the hair of the coat, existence of fatty deposits, and facial expression. ECA was significantly associated with two nutritional indicators, hematocrit and skin-fold thickness, but not with total serum proteins. For all dogs, hematocrit was significantly correlated with skin-fold thickness. The 2-year survival probability decreased significantly from 60.7% for dogs with good ECA to 45.9% and 31.2% for those with regular and bad ECA, respectively. The age-adjusted relative odds of infection for Triatoma infestans xeno-diagnosis nymphs that fed once on a dog seroreactive for Trypanosoma cruzi decreased significantly as ECA improved, when tested by multiple logistic regression analysis. A delayed hypersensitivity reaction was observed in all of the seroreactive dogs with good ECA but only in 45-50% of those with regular or bad ECA. Dogs with bad ECA had a 2.6 and 6.3 times greater probability of infecting triatomines after a single full blood meal than dogs with regular or good ECA, respectively. Our study shows that the reservoir competence of dogs for Trypanosoma cruzi was associated with ECA, which is a surrogate and valid index of nutritional state.

Domestic dog health worsens with socio-economic deprivation of their home communities

“…Dogs in Las Pavas were less likely to be infected with zoonotic pathogens ( Figure 5) than dogs in the communities that were less wealthy. While we did not found a strong significant correlation between body condition or site and T. cruzi infection, previous research has shown that malnutrition of dogs in Argentina lead to higher rates of canine T. cruzi infectivity to feeding vectors (Petersen et al 2001). If sampling was continued, we may potentially see a similar trend…”

“…The body condition score was then used as an indicator for health (Petersen et al 2001). Sex of each animal was also recorded.…”

Reservoir host competence and the role of domestic and commensal hosts in the transmission of Trypanosoma cruzi

“…Both the intensity and apparent duration of dog infectiousness were inversely correlated to an index of body condition reflecting health and nutritional status in two resource-constrained, endemic rural areas of the Argentine Chaco (Enriquez et al, 2014;Petersen et al, 2001). Domestic dogs almost invariably lacked veterinary supervision and vaccination against virulent canine diseases, and suffered from chronic malnutrition and anemia frequently associated with co-infections and protein-deficient diets.…”

Ecological patterns of blood-feeding by kissing-bugs (Hemiptera: Reduviidae: Triatominae)

“…1986). T. cruzi infections have also been related to nutritional indicators (Petersen et al 2001), principally cleptohaematophagy, in some triatomine species (Sandoval et al 2000). Only a few studies have focused on the quantitative estimation of feeding under natural conditions (Rabinovich et al 1979, Lopez et al 1999.…”