Implications of co-infection ofLeptomonasin visceral leishmaniasis in India

SUMMARYProtozoan parasitesLeishmania donovani(family: Trypanosomatidae) cause fatal visceral leishmaniasis (VL) and the infection relapses in apparently cured population as post kala-azar dermal leishmaniasis (PKDL) in the Indian subcontinent. In recent years co-infection of another Trypanosomatid parasiteLeptomonaswithL. donovaniduring VL/PKDL in this region has become prominent. The observation of clinically lesser-known insect parasite,Leptomonasin leishmaniasis is intriguing to researchers. The presence of Leishmania look alikeLeptomonasin the cultures of clinical isolates ofLeishmaniahas been worrisome to those, who prefer to work with pureLeishmaniacultures for drug and vaccine development or immune response studies. The exact implications of such a co-habitation, which might lead to a delay in the diagnostics of VL and elevate mortality, need a thorough investigation. Also whetherLeptomonasis involved in leishmaniasis manifestation needs to be ascertained. Thus we are currently witnessing a new paradigm of a parasitic co-infection in VL/PKDL cases in India and this review outlines various opportunities for further research in understanding such emerging co-infection.

A role for antimicrobial peptides in intestinal microsporidiosis

SUMMARYClinical isolates from 3 microsporidia species,Encephalitozoon intestinalisandEncephalitozoon hellem, and the insect parasiteAnncaliia(Brachiola, Nosema) algerae, were used in spore germination and enterocyte-like (C2Bbe1) cell infection assays to determine the effect of a panel of antimicrobial peptides. Spores were incubated with lactoferrin (Lf), lysozyme (Lz), and human beta defensin 2 (HBD2), human alpha defensin 5 (HD5), and human alpha defensin 1 (HNP1), alone and in combination with Lz, prior to germination. Of theEncephalitozoonspecies onlyE. hellemspore germination was inhibited by HNP1, whileA. algeraespore germination was inhibited by Lf, HBD2, HD5 and HNP1, although HBD2 and HD5 inhibition required the presence of Lz. The effects of HBD2 and HD5 on microsporidia enterocyte infection paralleled their effects on spore germination. Lysozyme alone only inhibited infection withA. algerae, while Lf inhibited infection byE. intestinalisandA. algerae. HNP1 significantly reduced enterocyte infection by all 3 parasite species and a combination of Lf, Lz and HNP1 caused a further reduced infection withA. algerae. These data suggest that intestinal antimicrobial peptides contribute to the defence of the intestine against infection by luminal microsporidia spores and may partially determine which parasite species infects the intestine.

A case of bilateral microsporidial keratitis from Bangladesh – infection by an insect parasite from the genus Nosema

An HIV-negative patient from Bangladesh with bilateral keratitis was found to be infected with a microsporidian parasite belonging to the genus Nosema. Significantly, the patient had bathed in a rural pond 7 days prior to the development of ocular symptoms. Nosema parasites are common insect parasites and the source of this microsporidial infection was possibly from mosquito larvae developing in the pond in which the patient bathed. The reduced temperature of the human eye and its immune status may have allowed a poikilothermic insect parasite to establish infection in the cornea of a homeothermic human host. This case highlights the opportunistic potential of insect microsporidial parasites to infect immunocompetent humans as well as those who are immunodeficient.

A note on the use of microbial insecticides for the control of tomato hornworms on flue-cured tobacco

Two formulations of Bacillus thuringiensis, Bactospeine-A and Thuricide-HPC, were applied on tobacco plants after topping to evaluate their effectiveness against tomato hornworm (Manduca quinquemaculata) in the laboratory and field. Both materials, regardless of the rates applied, gave complete control of the tomato hornworms. All the larvae fed slightly or moderately on the treated leaves during the first day after treatment, but thereafter, the larvae remained inactive on the treated leaves until death. There was little evidence of further feeding when the leaves were examined. The microbial insecticides had no detrimental effect on the beneficial insect parasite, Cotesia congragata, and no phytotoxicity was observed.