Phasing of the Triatoma virus diffraction data using a cryo-electron microscopy reconstruction.

The blood-sucking reduviid bug Triatoma infestans, one of the most important vector of American human trypanosomiasis (Chagas disease) is infected by the Triatoma virus (TrV). TrV has been classified as a member of the Cripavirus genus (type cricket paralysis virus) in the Dicistroviridae family. This work presents the three-dimensional cryo-electron microscopy (cryo-EM) reconstruction of the TrV capsid at about 25 A resolution and its use as a template for phasing the available crystallographic data by the molecular replacement method. The main structural differences between the cryo-EM reconstruction of TrV and other two viruses, one from the same family, the cricket paralysis virus (CrPV) and the human rhinovirus 16 from the Picornaviridae family are presented and discussed.

Effects of Triatoma virus (TrV) on the fecundity and moulting of Triatoma infestans (Hemiptera: Reduviidae).

Triatoma virus (TrV) is a Picorna-like virus affecting Triatoma infestans (Klug, 1834), the most important transmitter of Trypanosoma cruzi in South America. The subjects of the present, laboratory study were the longevity and oviposition of female Tri. infestans, from stocks with and without viral infection, and the survivorship and developmental time of their progeny through to second-instar nymphs. On average, adult females from an infected stock lived only a third as long as those from the uninfected, and the mean monthly egg outputs of the 'infected' females was only 20% of that of the uninfected females. Even though the virus can be transmitted transovarially and most, if not all, of the progeny of the infected females were themselves infected, there was no evidence for TrV affecting egg hatchability. A much smaller proportion of the progeny of the females from infected stock than of that of the uninfected females successfully moulted to second-instar nymphs (44% v. 80%); the virus appears to inhibit the moulting process. The progeny of the females from the infected stock developed relatively slowly, spending a mean of 6.1 days as first instars (compared with 3.9 days for the progeny of uninfected females). Together, these data indicate that TrV may be a useful agent for the biological control of Tri. infestans.

Direct methods for detecting picorna-like virus from dead and alive triatomine insects.

In this work we report four different destructive and non-destructive methods for detecting picorna-like virus particles in triatomines. The methods are based on direct observation under transmission electron microscope and they consist of four ways to prepare samples of presumable infected material. The samples are prepared processing dead or alive insect parts, or even dry or fresh insect feces. The methods can be used as analytical or preparative techniques, for quantifying virus infection and checking virus integrity as well. In this work the four methods are applied in order to detect Triatoma virus (TrV) particles in T. infestans colonies.

Direct methods for detecting picorna-like virus from dead and alive Triatomine insects

In this work we report four different destructive and non-destructive methods for detecting picorna-like virus particles in triatomines. The methods are based on direct observation under transmission electron microscope and they consist of four ways to prepare samples of presumable infected material. The samples are prepared processing dead or alive insect parts, or even dry or fresh insect feces. The methods can be used as analytical or preparative techniques, for quantifying virus infection and checking virus integrity as well. In this work the four methods are applied in order to detect Triatoma virus (TrV) particles in T. infestans colonies.