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Triatominae is a subfamily of Reduviidae, order Heteroptera; also known as conenose bugs, assassin bugs or kissing bugs. All the ~130 species of this group are haematophageous, i.e. feed on vertebrate blood. They are mainly widespread in America, with some few species in Asia, Africa and Australia. These bugs usually share shelter with nesting vertebrates, from which they suck blood.

All triatomine species are potential vectors of Chagas disease but, only those species (such as Triatoma infestans and Rhodnius prolixus) that are well adapted to live with humans are considered important vectors of the Chagas disease parasite (i.e. Trypanosoma cruzi).

In 1909 the Brazilian doctor Carlos Chagas discovered that these insects were responsible for the transmission of T. cruzi to many of his patients, as he put it in words: "Knowing the domiciliary habits of the insect, and its abundance in all the human habitations of the region, we immediately stayed on, interested in finding out the exact biology of the barbeiro, and the transmission of some parasite to man or to another vertebrate.

Herman Lent, who after being student of Carlos Chagas became devoted to the study of the triatomines, together with Peter Wygodzinsky, made a revision work of the Triatominae that was published in the Bulletin of the American Museum of Natural History (New York), 163 (3):125-520, figures 1-320, 1979, a summary of his 40 years of studies on the triatomines up to that time.

The main vectors of Chagas disease are:

Description by Charles Darwin

Description from Charles Darwin's Journal and Remarks, commonly known as The Voyage of the Beagle; Extract from entry for 25 March 1835:

"We crossed the Luxan, which is a river of considerable size, though its course towards the sea-coast is very imperfectly known: it is even doubtful whether, in passing over the plains, it is not evaporated and lost. We slept in the village of Luxan, which is a small place surrounded by gardens, and forms the most southern cultivated district in the Province of Mendoza; it is five leagues south of the capital. At night I experienced an attack (for it deserves no less a name) of the Benchuca, a species of Reduvius, the great black bug of the Pampas. It is most disgusting to feel soft wingless insects, about an inch long, crawling over one's body. Before sucking they are quite thin, but afterwards they become round and bloated with blood, and in this state are easily crushed. One which I caught at Iquique, (for they are found in Chile and Peru,) was very empty. When placed on a table, and though surrounded by people, if a finger was presented, the bold insect would immediately protrude its sucker, make a charge, and if allowed, draw blood. No pain was caused by the wound. It was curious to watch its body during the act of sucking, as in less than ten minutes it changed from being as flat as a wafer to a globular form. This one feast, for which the benchuca was indebted to one of the officers, kept it fat during four whole months; but, after the first fortnight, it was quite ready to have another suck."

Aspects

  • Ecology:

Triatomines are haematophagous insects: all five triatomine nymph instars and adults require blood to survive. They also require the stability of a sheltered environment. Most species are associated with wild nesting vertebrates and are named "sylvatic" triatomines. These live in ground burrows with rodents or armadillos, or in tree-dwellings with bats, birds, sloths or opossums. Few species (5%) live in human dwellings or in the surrundings of human houses (peridomicile), near the shelters of domestic animals; these are named "domestic" species. Domestic and sylvatic species carry the Chagas parasite to humans and wild mammals, respectively. Birds are immune to the parasite. Many sylvatic species are in process of domiciliation ("semidomestic").

  • Epidemiology:

Chagas transmission is carried mainly from human to human by domestic kissing bugs. T. cruzi parasite is transmited from the vertebrate to the bug by blood, and from the bug to the vertebrate by the insect's faeces and not by its saliva, as occurs in most bloodsucking arthropod vectors such as Malaria mosquitoes.

Triatomine infestation specially affects poor people. One can recognize the presence of triatomines in a house by its faeces. Triatomines characteristically leave 2 kinds of feces like strikes on walls of infected houses, one is white with uric acid, the other is dark (black) containing haem. Whitish eggs can be seen in crevices of the wall.

(After having had a blood meal the insects sometimes show a limited mobility, as they are found resting on walls, probably incapable to fly...)

Tribes, Genera and numbers of described species

-

fat: containing species are possibly able to transmit Trypanosoma cruzi to humans (Chagas).

Total Number of Triatominae species: 137.

The number of species which are suspected or have shown to be able to transmit Trypanosoma cruzi: 79;

47 of these belong to the genus Triatoma.

--- note: Taxonomy is changing due to new research, e.g. see:
  • Galvão C, Carcavallo R, da Silva Rorcha D, Jurberg J (2004) A checklist of the current valid species of the subfamily Triatominae Jeannel, 1919 (Hemiptera, Reduviidae) and their geographical distribution, with nomenclatural and taxonomic notes. Zootaxa 202: 1-36*

References

  • Brenner RR,Stoka AM (1987) Chagas’ disease vectors. I, II and III. CRC Press. Boca Raton

  • Dujardin JP, Shcofield CJ, Panzera F (2000) Les vecteurs de la maladie de Chagas: recherches taxonomiques, biologiques et génétiques. Academie Royale des Sciences d'Ultre-Mer. Belguium.

  • Dunston PA (1999) Assassin Bugs. Science Publishers Inc., Enfield, New Hampshire. 337 pp.

  • ECLAT = European Community Latin American Network for Research on the Biology and Control of Triatominae *

  • Galvão C, Carcavallo R, da Silva Rorcha D, Jurberg J (2004) A checklist of the current valid species of the subfamily Triatominae Jeannel, 1919 (Hemiptera, Reduviidae) and their geographical distribution, with nomenclatural and taxonomic notes. Zootaxa 202: 1-36

  • Lent H, Wygodzinsky P (1979) Revision of the Triatominae (Hemiptera, Reduviidae), and their significance as vectors of Chagas disease. Bull Am Mus Nat Hist 163:123–520

  • Maldonado-Capriles, Jenaro (1990) Systematic Catalogue of the Reduviidae of the World. Special Edition of the Caribbean Journal of Science. University of Puerto Rico, Mayaguez, Puerto Rico. 694 pp.*

  • Otálora-Luna F (2006) Chemosensory and behavioural adaptations for haematophagy in triatomine bugs (Heteroptera: Reduviidae). Université de Neuchâtel.

  • Schofield CJ (1994) Triatominae: biology & control. Eurocommunica Publications. West Sussex. UK 80 pp.

  • Schofield CJ (2000) Biosystematics and evolution of the Triatominae. Cad. Saúde Pública. vol.16 suppl.2 *. ISSN 0102-311X.

  • Zeledón R (1981) El Triatoma dimidiata (Latreille, 1811) y su relación con la enfermedad de Chagas. Editorial Universidad Estatal a Distancia. Costa Rica

  • Zeledón R, Rabinovich (1981) Chagas' disease: an ecological appraisal with special emphasis on its insect vectors. Annu Rev Entomol 26:101-33 *

See also

External links

Google picture search

The pictures will give an overview of the main morphology of the main vectors. Today, other species could be also important for the transmission of chagas disease. Some of the pictures could be "open source" also and should be considered to be included in wikipedia (!).

Other

Hemiptera

Triatominae

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Triatominae".

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