Let there be (UV) light

Vinchucas (Triatoma infestans) are carriers of Trypanosoma cruzi, the parasite causing Chagas-Mazza disease, an endemic pathology affecting different countries in Latin America. Mainly affected areas in Argentina include the north and northwest parts of the country. Also known as American trypanosomiasis, the disease is one of Argentina’s main health problems for which no cure is available although different treatments have been developed to lessen its effects. Parasites may cause heart disease and lesions affecting the digestive and nervous systems and in view of the current status, prevention is key.

Now, a group of researchers at the Regional Center for Scientific Research and Technology Transfer (CRILAR) from the province of La Rioja, report the results of a study aimed at the early detection of vinchucas. Methods to clearly determine the risk of the spread of disease as well as the presence of these insects are crucial for the successful design and evaluation of programs to control the malady.
Researchers point to the use of ultraviolet (UV) light to expose vinchuca´s feces as an easy way for the early detection of these vectors. “Vinchuca detection through the use of UV light is based in the fluorescent properties of these insects’ droppings when exposed to that light wavelength”, said Silvia Catalá, researcher at the CRILAR and the paper’s main author (see Sources).

Vinchuca’s feces vary in color (yellow, black, white or colorless) and the study showed that, except when black, all other colors display different fluorescent intensities. Fluorescence is higher in more recent depositions and in materials such as ordinary and adobe bricks, wood, paper and plastic. Droppings on certain fabrics and cardboard showed weaker fluorescence. According to Catalá “if we consider brick and wood as the two most common materials found in humble rural homes, this technique would allow us for an efficient detection of these insects”. According to the paper, colorless urine can also be detected by this method.

The technique would also provide with a quick way for the early detection of vinchuca infestation, since it can estimate number of insects and date of depositions (fluorescence decreases over time).
Dr. Catalá indicated the existence of portable UV flashlights which are commercially available and would permit the early detection of vinchuca infestation before their number becomes harder to handle.

Sources:
www.agenciacyta.org.ar
Paper in Acta Tropica