Cone Nosed Bug
Family: Reduviidae (incl. Triatominae)
Triatoma infestans - Kissing-Bugs
Rhodnius prolixus - Kissing-Bugs
Platymeris biguttata - Assassin Bugs
Panstrongylus megistus - Cone-Nosed Bugs
These bugs are generally large insects; with the adults reaching a length of between 15-35mm.
Normally dark brown to black with cream, yellow or red markings down the sides.
These insects have two pairs of wings and sucking mouthparts. They have no uniformity to their forewings with the anterior part being leathery and the posterior part membranous. These are held folded flat on the back when at rest. The Reduviidae have a robust, curved three segmented rostrum which lies below the head on the underside of the body. In the blood-sucking Triatominae the rostrum is slender and straight. They have well developed legs for rapid walking.
Cone nosed bugs are associated particularly with rodents and other small burrowing mammals.
Infestation may be established in human habitation by the flying gravid female. They generally favour buildings with lots of cracks and crevices. e.g. one with wooden walls.
Cone nosed bugs have an incomplete metamorphosis; whereby the nymphs are miniature versions of the adults but do not have matured sex organs or wings.
Once mature the females will mate and take their first blood meal, approximately two weeks later the female will lay up to 200 eggs in cracks, crevices and other harbourages. The freshly laid eggs are pale pink and hatch some 10 days later, the empty egg cases are white.
The wingless first instar nymph will emerge from the egg and seek shelter for a few days before taking its first blood meal. There are 5 nymphal stages each resembling the adult in miniature form, except that they are missing wings and mature sex organs.
The immature cycle can last for several months with the adults living for 2 years.
At least 28 species of reduviid bugs of the genera Panstrongylus , Rhodnius , Eutriatoma, and Triatoma are naturally infected with Trypanosoma cruzi , the pathogen of Chagas Disease, also called trypanosomiasis. The mature trypanosomes are ingested by the bugs and pass through the many stages of the intestinal canal over 8 to 10 days. These fully formed Trypanosomes - 'metacyclic forms' - are passed out in the faeces of the insect as they feed. The host becomes infected when the faeces is rubbed into the skin.
Where the parasite enters the host a boil / oedema (caused by macrophages) and fluid may appear. This can lead to fever and the swelling of the nymph nodes, liver and spleen. Death can occur. The patient may recover but can in the long term suffer damage of the heart muscle and problems with the oesophagus and colon.
Diagnosis in Early stages is essential as treatment is only really effective during the early stages of infection.