The ability to rapidly and accurately diagnose leishmaniasis is a military priority. Testing was conducted to evaluate diagnostic sensitivity and specificity of field-expedient Leishmania genus and visceral Leishmania specific dual-fluorogenic, hydrolysis probe (TaqMan), polymerase chain reaction assays previously established for use in vector surveillance. Blood samples of patients with confirmed visceral leishmaniasis and controls without the disease from Baringo District, Kenya, were tested.
View Article and Find Full Text PDFThe timing of infection is closely determined in controlled human malaria infection (CHMI) studies, and as such they provide a unique opportunity to dissect changes in immunological responses before and after a single infection. The first Kenyan Challenge Study (KCS) (Pan African Clinical Trial Registry: PACTR20121100033272) was performed in 2013 with the aim of establishing the CHMI model in Kenya. This study used aseptic, cryopreserved, attenuated sporozoites administered by needle and syringe (PfSPZ Challenge) and was the first to evaluate parasite dynamics post-CHMI in individuals with varying degrees of prior exposure to malaria.
View Article and Find Full Text PDFBackground: Controlled human malaria infection (CHMI) studies, in which healthy volunteers are infected with Plasmodium falciparum to assess the efficacy of novel malaria vaccines and drugs, have become a vital tool to accelerate vaccine and drug development. CHMI studies provide a cost-effective and expeditious way to circumvent the use of large-scale field efficacy studies to deselect intervention candidates. However, to date few modern CHMI studies have been performed in malaria-endemic countries.
View Article and Find Full Text PDFBackground: Controlled human malaria infection (CHMI) studies increasingly rely on nucleic acid test (NAT) methods to detect and quantify parasites in the blood of infected participants. The lower limits of detection and quantification vary amongst the assays used throughout the world, which may affect the ability of mathematical models to accurately estimate the liver-to-blood inoculum (LBI) values that are used to judge the efficacy of pre-erythrocytic vaccine and drug candidates.
Methods: Samples were collected around the time of onset of pre-patent parasitaemia from subjects who enrolled in two different CHMI clinical trials.
Background: Controlled human malaria infection (CHMI) studies are a vital tool to accelerate vaccine and drug development. As CHMI trials are performed in a controlled environment, they allow unprecedented, detailed evaluation of parasite growth dynamics (PGD) and immunological responses. However, CHMI studies have not been routinely performed in malaria-endemic countries or used to investigate mechanisms of naturally-acquired immunity (NAI) to Plasmodium falciparum.
View Article and Find Full Text PDFVector Borne Zoonotic Dis
June 2013
Abstract Rickettsiae are obligate intracellular bacteria that cause zoonotic and human diseases. Arthropod vectors, such as fleas, mites, ticks, and lice, transmit rickettsiae to vertebrates during blood meals. In humans, the disease can be life threatening.
View Article and Find Full Text PDFWe performed diagnosis and species identification of parasites in lesion samples from suspected cutaneous leishmaniasis patients in four villages, three of which are in a known Leishmania tropica endemic region in Kenya. Samples were analyzed both by microscopy and PCR for Leishmania, and typed by an assay using four ribosomal DNA-based species-identification PCRs. The lesions were demonstrated to be caused by L.
View Article and Find Full Text PDFA nine year aged male presented with facial lesions and the problem of responding to conventional treatment of leishmaniasis. Multiple injections of antimony and several topical ointments had been administered in hospital but fresh lesions erupted with potential to disfigure. Smears examined from nodular lesions confirmed presence of Leishmania amastigotes and parenteral pentostam was commenced for over eight weeks.
View Article and Find Full Text PDFObjective: To estimate the sensitivity and specificity of the OligoC-TesT and nucleic acid sequence-based amplification coupled to oligochromatography (NASBA-OC) for molecular detection of Leishmania in blood from patients with confirmed visceral leishmaniasis (VL) and healthy endemic controls from Kenya.
Methods: Blood specimens of 84 patients with confirmed VL and 98 endemic healthy controls from Baringo district in Kenya were submitted to both assays.
Results: The Leishmania OligoC-TesT showed a sensitivity of 96.
Visceral leishmaniasis (VL) seroprevalence in Kenya is unknown because of the lack of a practical and accurate diagnostic test or surveillance system. A novel serological assay was used to estimate the seroprevalence of Leishmania-specific antibodies, and Global Information System and spatial clustering techniques were applied to study the presence of spatial clusters in Parkarin and Loboi villages in Baringo District in 2001. VL seroprevalences were 52.
View Article and Find Full Text PDFIn-vivo and in-vitro studies to determine the sensitivity of Plasmodium falciparum malaria to chloroquine and amodiaquine were conducted in 4 districts of Western Kenya over a 2-year-period. Patients aged 5-60 years, were treated with chloroquine or amodiaquine base 25 mg/kg over 3 days. Recurrence of parasitaemia within 7 days (R1 resistance) or failure to clear parasites (R11 resistance) was observed in 27% of infections in West Pokot district, 51% in Busia, 45% in Bungoma and 19% in Rusinga Island.
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