Conenose Bug

The members of the Triatominae , a subfamily of the Reduviidae, are also known as conenose bugs, kissing bugs (so-called from their habit of feeding from around the mouths of people), or vampire bugs. Other local names for them used in the Americas include ''barbeiros'', ''vinchucas'', ''pitos'', ''chipos'' and ''chinches''. Most of the 130 or more species of this subfamily feed on vertebrate blood; a very small portion of species feed on invertebrates. They are mainly found and widespread in the Americas, with a few species present in Asia and Africa. These bugs usually share shelter with nesting vertebrates, from which they suck blood. In areas where Chagas disease occurs (from the southern United States to northern Argentina), all triatomine species are potential vectors of the Chagas disease parasite ''Trypanosoma cruzi'', but only those species that are well adapted to living with humans (such as ''Triatoma infestans'' and ''Rhodnius prolixus'') are considered important vectors. Also, proteins released from their bites have been known to induce anaphylaxis in sensitive and sensitized individuals.

History

At the beginning of the 19th century, Charles Darwin made one of the first reports of the existence of triatomines in America in his ''Journal and Remarks'', published in 1839 and commonly known as ''The Voyage of the Beagle''. The following is an extract which he based on his journal entry dated 26 March 1835:

Considerable medical speculation has occurred as to whether or not Darwin's contact with triatomines in Argentina was related to his later bouts of long-term illness, though it is unlikely to have been caused on this specific occasion, as he made no mention of the fever that usually follows the first infection.

Modelling of the geographical distribution of triatomines in Chile shows that Darwin traveled extensively in the areas of central and northern Chile where these bugs occur, sleeping outdoors and in rural houses.

Discovery of link to Chagas disease

In 1909, Brazilian doctor Carlos Chagas discovered that these insects were responsible for the transmission of ''T. cruzi'' to many of his patients in Lassance, a village located on the banks of the São Francisco River in Minas Gerais (Brazil). Poor people living there complained of some insects they called ''barbeiros'' that bite during the night. Carlos Chagas put his first observations in words:

Another Brazilian, Herman Lent, former student of Carlos Chagas, became devoted to the research of the triatomines and together with Peter Wygodzinsky made a revision of the Triatominae, a summary of 40 years of studies on the triatomines up to 1989.

Biological aspects

Life cycle

Triatomines undergo incomplete metamorphosis. A wingless first-instar nymph hatches from an egg, and may be small as 2 mm. It passes successively through second, third, fourth, and fifth instars. Finally, the fifth instar turns into an adult, acquiring two pairs of wings.

Ecology

All triatomine nymph instars and adults are haematophagous and require the stability of a sheltered environment, where they aggregate. Most species are associated with wild, nesting vertebrates and are named "sylvatic

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