Performance of Quantitative Buffy Coat, QBC Fluorescence and Staining Technologies™ Test, and SD Bioline™ Malaria Rapid Test in Malaria Diagnosis in Western Kenya

Malaria remains the most important parasitic disease in sub-Saharan Africa as a cause of morbidity and mortality.  Effective management of malaria relies on prompt and accurate diagnosis to guide treatment.  The World Health Organization (WHO) recommends that all suspected malaria cases be tested before initiation of treatment, thus diagnosis of malaria requires parasitological confirmation of malaria parasites in the blood of suspected patients.  This cross-sectional study conducted at the Ahero County Hospital, Kisumu, Kenya, evaluated the performance of quantitative buffy coat (QBC) (QBC Fluorescence and Staining Technologies™(QBC F.A.S.T.™)-improved QBC system and SD Bioline™ malaria rapid tests) against 'gold standard' (Giemsa blood stained slides microscopy) for the detection of Plasmodium species in children<five years old (n=385)in a malaria holo-endemic area of western Kenya.  Real-time PCR was performed on discrepant samples across the tests and the gold standard (microscopy).Sensitivity of QBC, QBC F.A.S.T.™ and SD Bioline™ malaria rapid tests were 90% (95% CI: 85-94), 77% (95% CI: 71-83) and 91% (95% CI: 86-94), respectively, while specificity was 30% (95% CI: 24-37), 83% (95% CI: 77-88) and 67% (95% CI: 60-73), respectively.  The positive predictive values (PPV) were 58% (95% CI: 52-63), 83% (95% CI: 77-88) and 74% (95% CI: 63-80), respectively, while the negative predictive values (NPV) were 74% (95% CI: 63-84), 78% (95% CI: 71-83) and 87% (95% CI: 81-92), respectively.Although the standard QBC malaria test and the SD Bioline™ malaria rapid diagnostic test (RDT) showed better sensitivity relative to the improved QBC F.A.S.T.™ test, the latter had a better specificity.  The performance of these tests remains modest against microscopy. Keywords: Malaria, Quantitative buffy coat, QBC F.A.S.T.™, SD Bioline

Coxiella burnetii Detected in Tick Samples from Pastoral Communities in Kenya

Ticks are important disease vectors in Kenya with documented evidence of carriage of zoonotic pathogens. Coxiella burnetii is an important tick-borne pathogen that is underreported in Kenya and yet this infection likely contributes to undiagnosed febrile disease in pastoral communities. Archived human blood (278) and tick pool samples (380) collected from five pastoral communities in Kenya were screened for C. burnetii by PCR using primers targeting the transposon-like IS1111 region. All the human blood samples were negative for C. burnetii DNA. However, C. burnetii was detected in 5.53% (21/380) of the tick pools tested. Four of the twenty-one PCR positive samples were sequenced. The findings indicate that Coxiella burnetii was not present in the human blood samples tested. However, C. burnetii was detected in ticks from Mai Mahiu, Marigat, Ijara, Isiolo, and Garissa indicating a natural infection present in the tick vector that poses a risk to livestock and humans in these communities

Assessment of Molluscicidal, Cercericidal and Miracicidal Activities of Crude Extracts of Azadirachta indica and Entada leptostachya

Schistosomiasis infections in humans depend absolutely on the presence of intermediate host. Control of the intermediate host disrupts the cycle of schistosomes stopping transmission of schistosomiasis. Synthetic molluscicides used today are expensive and toxic to non-target organisms. Herbal preparations which do not affect non-target organisms would be a key in controlling schistosomiasis. This study was done to determine if plant extracts of Entada leptostachya and Azadirachta indica exhibit molluscicidal, cercericidal and miracicidal activities. Biomphalaria pfeifferi adult snails and juveniles, Schistosoma mansoni cerceriae and miracidia were used in the study. Groups of uninfected snails were exposed to different concentrations of water, methanol and ethyl acetate crude extracts obtained from the two plants. Controls were also set; positive control (Niclosamide) and negative control (Distilled water). Miracidia and cerceriae were exposed to the most active plant extract on juvenile and adult snails. Data analysis was done using Finney probit analysis to estimate the LD50 values of the crude extracts on snails and LT50values of the crude extracts on cerceriae and miracidia. Only methanol extract of E. leptostachya was found to exhibit the highest molluscicidal activity on juveniles and adults with a LD50 value of 30.21 mg/l and 40.93 mg/l respectively (P ? 0.05). Methanol extract of A. indica, aqueous and ethyl acetate extracts of A. indica and E. leptostachya were nontoxic to both adult and juvenile snails. On the other hand, methanol extract of E. leptostachya were found to have cercericidal and miracicidal activity. The LT50 of miracidia and cerceriae was 7.69 minutes and 4.25 minutes respectively at a concentration 80 mg/l (P ? 0.05). Phytochemical screening of the methanol, aqueous extracts and ethyl acetate extracts of A. indica and E. leptostachya confirmed the presence of flavonoids, saponins, tannins, alkaloids, triterpenes and sterols. Results suggest that methanolic root extract of E. leptostachya has molluscicidal activity against Biomphalaria pfeifferi. The results also indicate that methanolic root extract of E. leptostachya have cercaricidal and miracicidal activity against the schistosome larval stages. Keywords: Azadirachta indica,  Entada leptostachya, Biomphalaria pfeifferi, Crude extracts, Phytochemical screening, Molluscicidal activity, Cercericidal activity and Miracicidal activit

Cellular responses against Schistosoma mansoni in immunized Balb/c mice with soluble proteins from intermediate host, Biomphalaria pfeifferi

Scores of millions of people around the world are infected by Schistosoma mansoni causing considerable morbidity, mortality and loss of productivity. Safe chemotherapeutic agents have been used though there are challenges of re-infection due to resistance. Both epidemiological and experimental data suggest that acquired cell mediated immunity play significant roles in regulating the intensity of S. mansoni infection as well as its patho-physiologic sequelae. Improved control of this trematode parasite may be obtained with immunization to enhance the resistance of individuals to risk of infection. This study investigated the cellular responses of mice immunized with soluble proteins from foot and digestive gland of the vector snail and challenged with S. mansoni. The proteins were used to immunize the experimental groups then challenged with the S. mansoni. The experimental groups were FT (immunized with foot protein) and DG (immunized with digestive gland). The parameters, which were analyzed to demonstrate protection, included; the worm counts and cellular (IFN-γ, IL-5 cytokines) responses. It was observed that, the experimental groups showed significant protection in terms of worm reduction and immune responses. The group vaccinated with foot protein showed higher protection (87.5%) as compared to the group vaccinated with the digestive gland (50%) in terms of worm reduction. Cytokines (IFN-γ and IL-5) production was present in different levels during the assay time points which showed an aspect of protection. The Foot protein of the vector showed more immunizing power than the digestive gland. Research towards utilizing the two proteins as feasible vaccine candidates is encouraged

Ixodid ticks (Acari: Ixodidae) collected from African savanna elephants (Loxodonta africana) and African forest elephants (Loxodonta cyclotis)

Eight ixodid tick species were collected from 173 African savanna elephants (Loxodonta africana) in Kenya, northern Mozambique and Zimbabwe, and two species were collected from six African forest elephants (Loxodonta cyclotis) in the Republic of Congo. A new host record is reported for Amblyomma eburneum. A list of ticks collected from elephants in various African countries, and stored in the United States National Tick Collection, is supplied as well as an annotated checklist of the 27 ixodid tick species that have been collected from African elephants. The geographic distributions and alternative hosts of the various tick species collected from elephants are briefly discussed.Kenya Wildlife Service and the National Research Foundation (NRF) of South Africa.http://www.ojvr.orgpm2020Veterinary Tropical Disease