Biochemical Properties of Parasite Virulence Factor: Lesson Learned from Leishmania

Leishmania, a parasitic protozoan, a single-celled organism of the genus trypanosomes that are responsible for the disease leishmaniasis. Transmission occured by sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World. Globally, at least 93 sandfly species are proven or probable vectors. Their primary hosts are vertebrates; Leishmania commonly infects hyraxes, canids, rodents, and humans. Leishmaniasis encompasses diverse clinical syndromes, including cutaneous, mucosal, and potentially life-threatening visceral forms. Three widely known virulence factors belongs to the genus Leishmania include the active compound named proteophosphoglycan (PPG), GP63 metalloprotease and lipophosphoglycan (LPG). these substance established on the surface of the parasite. The aim of this review article is to make an insight of the biochemical characteristics of Leishmania spp virulence factors, the armamentarium that predispose their pathogenesis, its invasion and virulence to the mammalian host.

TRYPANOSOMA spp. in captive primates in a brazilian zoo

Captive animals, despite the constant care provided, are susceptible to infections from different sources. We herein report the natural trypanosome infection of 11 (28.2% positive) out of 39 non-human primates from 13 different species, in a Brazilian zoological park. Immunofluorescent antibody test (IFAT) and conventional polymerase chain reaction (cPCR) ruled out Trypanosoma cruzi, the etiological agent of Chagas disease. However, sequencing performed with positive samples employing hsp70 primers revealed similarities from 86% to 88% to diverse trypanosomes, including T. cruzi, Trypanosoma grayi, Trypanosoma lewisi, Trypanosoma rangeli and Trypanosoma vivax. We believe that the low similarity values obtained by sequencing reflect the difficulties in the molecular identification of trypanosomes, which share a large portion of their genetic material; this similarity may also preclude the diagnosis of co-infection by more than one trypanosome species. Thus, our study demonstrates the presence of diverse trypanosomes in primates, which are susceptible to infection by these parasites. Mechanical devices such as windows and bed nets, etc., are required to avoid vector insects in these environments, in addition to preventive quarantining of animals recently introduced into zoos. Therefore, investigation of the parasites in both the animals already residing in the zoo and those being introduced is of paramount importance, although no easy task.

Comparative Studies of Therapeutic Effect of Leaves, Stem Bark and Root Bark Extracts of Afzelia africana (Smith) in Mice Challenged with Trypanosoma brucei brucei.

Background: Traditional and complimentary health care is inarguably the system most close to homes, accessible and affordable. It is also culturally acceptable and trusted by large numbers of people. The affordability of most traditional medicines makes them all the more attractive at a time of soaring health-care costs, neglect of orphaned/non profitable diseases and nearly universal austerity. Aim: Aqueous leaf, stem bark and root bark extracts were evaluated for their anti trypanosomal effect in experimental trypanosomiasis with a view to come up with a phytomedicine that is efficacious, available, accessible and non-toxic to both humans and animals. Study Design: Complete randomized clinical trial design was used in the experiment. Methodology: Ninety five (95) mice were grouped into three (I, II, III) of thirty mice each (with sub groups A, B, C, D, E, and F consisting of five mice each) to which the leaf, stem bark and root bark extracts were administered at a dose of 100, 200, 300, 400 mg/Kgbw, while the remaining five mice served as the control for all the groups. Results: The aqueous leaves extract at doses of 100, 200 and 300 mg/Kg bw portrayed very low activities except for the 400 mg/Kg bw that displayed a sustained Trypanostatic effect. The aqueous stem bark extract, at doses of 100 and 200 mg/Kg bw portrayed trypanostatic effect while doses of 300 and 400 mg/Kg bw effectively cleared the parasites from circulation on the 13th and 17th days into the treatment respectively. Three and two of treated mice survived and remained apparasitaemic for up to 120 days and beyond in the group treated with 300 and 400 mg/kg bw respectively. In the group treated with the root bark extract, the mice on a dose of 100 mg/Kg bw died some few days into the experiment (6th day) while the dose of 200 mg/Kgbw sustained the animals until the 19th day. Doses of 300 and 400 mg/Kg bw were observed to clear the parasites in circulation after sustained administration for 23 and 16 days respectively. Conclusion: This study has demonstrated the potency of the stem bark and root bark crude extracts of Afzelia africana in treating experimental trypanosomiasis and can thus be further purified and packaged as phytomedicine against this dreaded but neglected disease.

An Assessment of Immune Response to Canine Distemper Vaccination in Dogs Experimentally Infected with Ancylostoma and Trypanosome Parasites.

The immunological alteration in vaccinated dogs with single hookworm, Ancylostoma caninum (A. c) and conjunct infection with Trypanosoma congolense (T. c) and Trypanosoma brucei (T. b) was determined. Sixteen dogs grouped into 4 of 4 members each were used. Group 1 was the uninfected control, GPII was infected with A. c, GPIII was infected with A. c /T. c, and GPIV was infected with T. b/A. c. The dogs were first inoculated with canine distemper (CD) vaccine before infection with A. c 4 weeks post vaccination. Two weeks later, both GPIII and GPIV were superposed with trypanosome infection. Prepatent period of A. c was 14 to 16 days in single A. c group and 13 to 14 days in conjunct trypanosome/A. c. The prepatent period of conjunct T. c/A. c was 9.00±1.10 days and 3.00±1.40 days, in conjunct T.bb/A. c. The protective antibody against CDV was considered using haemagglutination inhibition test (HIT) titer >100 as a cut off for seroconversion. At one week post vaccinations, the antibody titer against canine distemper (CDV) and anti-rabies in all the vaccinated groups (GPI, GPII, GPIII, and GPIV) significantly increased (p<0.05) and peaked at 3 weeks post vaccination. Subsequently, there was gradual significant decrease (p<0.05) in all the infected groups (GPII, GPIII and GPIV). The decrease in the conjunct groups (GPIII and GPIV) was higher compared to the single infections (GPII). Treatment with diminazene aceturate and mebendazole in all the groups did not significantly (p<0.05) improve antibody response in the dogs. A secondary vaccination administered at 12 weeks post- primary vaccination significantly increased (p<0.05) the antibody titer with a peak 3 weeks post- secondary vaccination. In conclusion, both trypanosomes and A. c induced primary immune suppression in antibody response to vaccination which improved on secondary vaccination in the infected dogs.

Seroprevalencia de la infección chagásica: Comunidad “La Gavillera”, Parroquia Negro Primero. Estado Carabobo, Venezuela, 2007 / Seroprevalence of chagasic onfection: "La Gavillera" neighbourhood, Negro Primero Parish. Carabobo State, Venezuela, 2007

La Infección chagásica se ha convertido en expresión fiel de la problemática de salud de América Latina; siendo endémica en el área rural del estado Carabobo, se decidió realizar el levantamiento de la seroprevalencia. Objetivos: determinar la seroprevalencia de la infeccion chagasica, caracterizar las viviendas y estudio de la infestación por triatóminos de las mismas, con su respectiva taxonómia y estudio parasitológico de las heces de los vectores capturados. Estudio descriptivo, transversal y prospectivo. Como técnica de análisis se emplearon los promedios, desviación estándar y análisis porcentual. Resultados: El 20,9% de la población resultó seropositiva, en un 58,6% mujeres con promedio de edad de 48,7±13,9 años, y 46±12,68 años para los hombres. La mayoría de las viviendas eran de paredes de bahareque, techos de palma y pisos de tierra encontrándose en ellas un 20% de triatominos vectores; de estos, 81.9% fueron de especie Panstrongylus geniculatus; y Trypanosoma rangeli fue la especie parasitaria diagnosticada mayormente en los vectores. Las deficientes condiciones de vivienda observadas siguen favoreciendo el mantenimiento de la seroprevalencia chagásica en la muestra.

Chagasic infection has become an accurate sample of health problems in Latin America. Because of its endemicity in rural areas of Carabobo State, a seroprevalence survey was performed. Its aim was to determine prevalence of Chagasic infection, characterize human dwellings, triatomid infestation and their taxonomy and a parasitological determination of infection in collected vectors. A descriptive, cross tabulated and prospective pattern was applied. Average, standard deviation and percentage analysis were performed. 20.9% of the sample were positive and among them, 58.6% were females with an age average of 48.7+- 13.9 years and 46+- 12.68 years in males. Most of human dwellings were wattle and daub structures, with palm roofs and dirt ground. 20% of them infestated with vector triatomids, among them: 81.9%, were Panstrongylus geniculatus and Trypanosoma rangeli, was the most prevalent parasite. Conclusion aims that that deficiencies in human dwellings is the cause of maintenance of Chagasic seroprevalence assessed in the present survey.

Electron microscopy of trypanosomes: a historical view

Since the discovery of the electron microscope and the development of the initial techniques for the processing of biological samples for electron microscopy, the protozoan Trypanosoma cruzi has been the subject of intense investigation. This review analyzes the results obtained by observation of whole trypanosomes as well as thin sections and replicas using several microscopic approaches. Micrographs detailing the appearance of T. cruzi using several methods illustrate the evolution of electron microscopic techniques as well as its contribution to understanding the structural organization of the protozoan.

Trypanosoma (Duttonella) vivax: its biology, epidemiology, pathogenesis, and introduction in the New World - a review

The biology, epidemiology, pathogenesis, diagnostic techniques, and history of the introduction of Trypanosoma (Duttonella) vivax in the New World are reviewed. The two main immunological responses of trypanosome-infected animals - antibody production and immunodepression - are discussed in the context of how these responses play a role in disease tolerance or susceptibility. Isolation and purification of T. vivax are briefly discussed. The recent reports of bovine trypanosomiasis diagnosed in cattle on farms located in the Pantanal region of the states of Mato Grosso do Sul and Mato Grosso, Brazil, are also discussed.