Egg immunity in the Kissing bug – the carrier of Chagas disease

Egg immunity in the Kissing bug – the carrier of Chagas disease

Chagas disease is caused by the parasite Trypanosoma cruzi. Approximately 6-7 million people in South and Central America are infected. It can cause fever, headache, mucle pain, difficulty with breathing and chest pain. In later years of the infection it can lead to sudden death or heart failure. This parasite is transmitted by so called triatomine vectors, such as the kissing bug Rhodnius prolixus. This kissing bug needs to take several blood meals in order to grow and mature. When they take such a blood meal from an infected animal they can spread this disease to its next victim. They infect a new victim because the parasite travels through the bug’s intestines and ends up in their faeces (poo). When they bite they make a hole in the skin, once they are done feeding they tend to defecate pretty quickly and often near their feeding site. In this way the parasites are able to enter the body of the victim and infect him or her.

There are several ways in which the number of kissing bugs are controlled, which include spraying pesticides, biological control by using insects that parasitize the eggs of the kissing bug and dispersing microbial pathogens to kill the insects. However, any method aimed at controlling kissing bug numbers strongly relies on our knowledge of how they can counteract our control measures. If the insect’s immune system can counteract the microbial pathogens we spread, this control measure isn’t effective.

Although eggs do not directly spread Chagas disease, they can cause re-infestation of a house. When a control measure is able to kill all adults but not the eggs, a house is quickly re-infested again after the eggs hatch. Unfortunately, at this time we have no idea whether the eggs are resistant to infections or not. Therefore we want to find out if the eggs of the kissing bugs are able to resist infections by looking at their immune response.

What will we do:

This project will be performed in collaboration with assistant professor Rodrigo Nunes da Fonseca of the Federal University of Rio de Janeiro in Brazil. We will create 3 different egg groups: 1) normal untreated eggs, 2) eggs stabbed with a sterile needle and 3) eggs infected with bacteria. From these different groups we will extract the RNA. By measuring the amount of RNA for immune genes in each group we can see if they get more active when an egg is infected. We will look at, among others, so called antimicrobial peptides. These are proteins specifically produced to kill bacteria and fungi. If the genes for these antimicrobial peptides get more active after infection, it is likely that these eggs are able to fight the infection and increase their survival. This has important implications for which measures we can use to kill eggs.

What we need:

 Of course doing experiments costs money. The experiments we plan to do here require some materials like needles, materials for the RNA extraction and materials needed to measure gene activity. The total budget we need to complete this project is €2250,-

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