Rhaiza Maingon

The Leishmania hertigi (Kinetoplastida; Trypanosomatidae) Complex and the Lizard Leishmania: Their Classification and Evidence for a Neotropical Origin of the Leishmania-Endotrypanum Clade

ABSTRACT. The relationships of the Leishmania hertigi complex and the lizard Leishmania species to the main groups of mammalian Leishmania and Endotrypanum parasites were examined. Restriction fragment length polymorphisms and sequences of small subunit ribosomal RNA genes and hybridization studies of kinetoplast DNA indicated that the L. hertigi complex was more closely related to the genus Endotrypanum than to the genus Leishmania. The lizard Leishmania species were found to be at the crown of the Leishmania tree. The data provides strong evidence for a Neotropical origin of the Endotrypanum/Leishmania clade since the parasites closest to the root of the tree are all found exclusively in the Neotropics. The evolution of the Leishmania/Endotrypanum clade in relation to the evolution of the known hosts of these parasites is discussed.

The sandfly Lutzomyia longipalpis shows specific humoral responses to bacterial challenge.

Abstract The presence of immune molecules induced by microorganisms in the haemolymph of Lutzomyia longipalpis sandflies has been investigated. Injections of Escherichia coli and Micrococcus luteus into female sandflies induced anti‐bacterial activity in the haemolymph. Inhibition zone assays showed that haemolymph from E.coli and M.luteus injected sandflies differentially inhibited M.luteus growth. This differential effect was specific to M. luteus infection since anti‐Zs. coli activity was similar in haemolymph from both E.coli oxM.luteus injected sandflies. Haemolymph following injection of either bacteria showed the induction of a 4kDa peptide. Haemolymph from M.luteus injected sandflies also contained a 33 kDa polypeptide which was absent in haemolymph from E.coli and control uninfected insects. Sandflies, in common with other insects, were shown to possess general and specific humoral immune responses to the presence of microorganisms.

Molecular techniques in the characterization of Leishmania isolates from Central America

The public-health problems caused by leishmaniasis in most countries in Central America are becoming more severe. This is partly because of the increasing size of the human populations that are at risk and their migratory patterns. Annual incidence of the disease in Costa Rica, Honduras, Guatemala, Panama and Nicaragua is estimated to be as high as 20,000 cases. Regional changes in the epidemiology of the various Leishmania spp. present have emphasized the need for innovative, sensitive and accurate diagnostic tools. PCR and isoenzyme, monoclonal antibody, schizodeme, DNA-probe and random-amplified, polymorphic DNA analyses have been tested. Preliminary indications that Leishmania chagasi was present in Costa Rica and Honduras and that interspecific hybrids occurred in Nicaragua have been confirmed using these methods. The distribution of the mexicana complex was also found to be broader and more heterogeneous than initially expected. Overall, there was 87% concordance between the results produced using the different techniques.

A morphologically distinct Phlebotomus argentipes population from active cutaneous leishmaniasis foci in central Sri Lanka

Although the reported aetiological agent of cutaneous leishmaniasis (CL) in Sri Lanka is Leishmania donovani, the sandfly vector remains unknown. Ninety-five sandflies, 60 females and 35 males, collected in six localities in the district of Matale, central Sri Lanka, close to current active transmission foci of CL were examined for taxonomically relevant characteristics. Eleven diagnostic morphological characters for female sandflies were compared with measurements described for Indian and Sri Lankan sandflies, including the now recognised Phlebotomus argentipes sensu lato species complex. The mean morphometric measurements of collected female sandflies differed significantly from published values for P. argentipes morphospecies B, now re-identified as Phlebotomus annandalei from Delft Island and northern Sri Lanka, from recently re-identified P. argentipes s.s. sibling species and from Phlebotomus glaucus. Furthermore, analysis of underlying variation in the morphometric data through principal component analysis also illustrated differences between the population described herein and previously recognised members of the P. argentipes species complex. Collectively, these results suggest that a morphologically distinct population, perhaps most closely related to P. glaucus of the P. argentipess. I. species complex, exists in areas of active CL transmission. Thus, research is required to determine the ability of this population of flies to transmit cutaneous leishmaniasis.

Polymerase chain reaction detection of Leishmania DNA in skin biopsy samples in Sri Lanka where the causative agent of cutaneous leishmaniasis is Leishmania donovani

Leishmania donovani is the known causative agent of both cutaneous (CL) and visceral leishmaniasis in Sri Lanka. CL is considered to be under-reported partly due to relatively poor sensitivity and specificity of microscopic diagnosis. We compared robustness of three previously described polymerase chain reaction (PCR) based methods to detectLeishmania DNA in 38 punch biopsy samples from patients presented with suspected lesions in 2010. Both, Leishmaniagenus-specific JW11/JW12 KDNA and LITSR/L5.8S internal transcribed spacer (ITS)1 PCR assays detected 92% (35/38) of the samples whereas a KDNA assay specific forL. donovani (LdF/LdR) detected only 71% (27/38) of samples. All positive samples showed a L. donovani banding pattern upon HaeIII ITS1 PCR-restriction fragment length polymorphism analysis. PCR assay specificity was evaluated in samples containing Mycobacterium tuberculosis, Mycobacterium leprae, and human DNA, and there was no cross-amplification in JW11/JW12 and LITSR/L5.8S PCR assays. The LdF/LdR PCR assay did not amplify M. leprae or human DNA although 500 bp and 700 bp bands were observed in M. tuberculosis samples. In conclusion, it was successfully shown in this study that it is possible to diagnose Sri Lankan CL with high accuracy, to genus and species identification, using Leishmania DNA PCR assays.

Leishmaniasis, health services and epidemiology: Avenues for a needed partnership

This meeting aimed at Iplacing leishmaniasis within primary health care and community participation. Biochemists, parasitologists and entomologists joined the public health specialists to discuss the feasibility of :some of the promising new technologies and tools for diagnosis and control of the disease in tropical and Mediterranean areas. However sensitive and specific molecular diagnostic and intervention reagents promise to be, these have to be demanded and accepted by the affected population and, at the same time, be feasible to implement within the health services and communities (P. Mercenier, Institute of Tropical Medicine, Antwerp, Belgium; A. Kroeger, Liverpool School of Tropical Medicine, UK). This was illustrated by experiences in community partic:ipation, vector control and primary health care in Peti (A. Llanos-Cuentas, Universidad Peruana Cayetano Heredia, Lima), Colombia (C. Rojas, CIDEIM Foundation, Cali) and in the West-Bengal region of India (A. Nan’dy, Calcutta School of Tropical Medicine). One of the highlights of the workshop was a field trip to Sidi Bouzid, ;s pet-i-urban focus of cutaneous leishmaniasis due to Leishmania major, where an integrated reservoir-control pilot project based on basic health care, is taking place.