Biology subjects

Grace, D.

Publications and source records attributed to Grace, D..

3 recordsLinked to original sources

bioRxiv2020

Leptospira spp. seroprevalence in humans involved in a cross-sectional study in Garissa and Tana River Counties, Kenya

IntroductionLeptospirosis is a neglected bacterial zoonotic infection caused by spirochetes of Leptospira genus. Humans get infected through direct or indirect contact with urine of infected animals or environment. It accounts for more than 300,000 severe cases annually worldwide with case fatality rates of over 30%. Costs of diagnosis and treatment for human and animals, disruption of international trade of animals and products, reduced productivity and reproductivity in animals constitute economic importance. In Kenya, leptospirosis burden is significant but under-diagnosis and under-reporting affects the awareness of the disease. This study aimed to determine and compare the sero-prevalence and factors associated with Leptospira spp. in the two counties. MethodsWe conducted a cross-sectional study that involved apparently healthy people of at least 5 years of age in randomly selected households in Garissa and Tana River Counties. Blood samples were collected and tested for Leptospira spp antibodies using IgM ELISA. Standardized structured questionnaires were administered to collect socio-demographic and exposure information. We calculated frequencies and proportions for categorical variables and odds ratios (OR) and 95% confidence interval (CI) to evaluate association between sero-positivity and exposure factors. We used Wilcoxon test to evaluate statistical difference in sero-positivity for continuous variables and calculated test statistic (H) and p-value. ResultsA total of 952 subjects were recruited into the study - these included 482 persons from Garissa and 470 from Tana River. The overall sero-prevalence was 26% [(244/952); (CI: 23% to 29%)]. Garissa County had significantly higher Leptospira spp. seroprevalence (31%, n = 147; CI: 27% to 35%) compared to Tana River County (21 %, n = 97; CI: 17% to 25%). Being a female (OR=1.6, CI: 1.2-2.2) and engaging in pastoralism (OR=2.7, CI: 1.8-3.9) were significantly associated with higher odds of Leptospira spp. seropositivity compared to being a male or working in irrigated areas. The mean altitude of residence of sero-positive patients was 73m {+/-} 21 SD (standard deviation) above sea level and that for sero-negative was 80m {+/-} 22 SD (H=35, p-value = 0.00). ConclusionThis study determined the seroprevalence and risk factors for Leptospira spp. exposure in Garissa and Tana River Counties, Kenya. Females in pastoral communities experience high burden of the disease. Enhanced surveillance in humans and animals and further research is required to understand the complex and multifactorial drivers of leptospirosis transmission in the two Counties.

microbiology↗

bioRxiv2019

Food-borne mycotoxin hazards in the Kenyan market-a retrospective study

Mycotoxin contamination data (n=1818) in feed and food from major laboratories were categorized into hazardous and non-hazardous using contaminants regulatory limits, analyzed by logistic regression and chi-square test to identify potential health hazards. Feeds were most contaminated, with 64% and 39% having total aflatoxin (AFT) levels above Kenyan and American standards respectively. Peanuts, the most contaminated food, had 61% and 47% of samples failing Kenyan and American AFT standards respectively. By European standards, wheat had highest AFT contamination rate of 84%. Half of baby foods sampled had AFT level above Kenyan and European standards. Maize had failure rates of 20% (Kenyan standard), 14% (American standard) and 25% (European standard) for AFT. We observed high frequency of mycotoxins (AFT, aflatoxin M1, zearalenone, T-2 toxin, ochratoxin A, fumonisins, deoxynivalenol) and AFT hazards with significantly (p<0.001) higher failure rates in wheat, peanuts, mycotoxin hazards in dairy products in that order (European standard). Failure rates were significantly (p<0.001) higher in feed ingredients (p<0.01), baby foods (p<0.05), maize (p<0.001), fodder (p<0.05) for mycotoxins, and compound feeds, peanuts, wheat (p<0.001), feed ingredients, baby foods (p<0.01), maize (p<0.001), fodder (0.01), in that order, for AFT (American standard). Fail rates were significantly higher for mycotoxins in compound feeds, feed ingredients, peanuts, wheat, baby foods, maize (p<0.001), herbal health drink (p<0.01), and for AFT in compound feeds, feed ingredients, peanuts, wheat (p<0.001), baby foods (p<0.01), herbal health drink (p<0.05), maize (p<0.001) in that order (Kenyan standard). High frequency of mycotoxin and AFT hazards in maize, baby foods, herbal health drink and aflatoxin M1 in dairy products was noted. Detection by different laboratories varied significantly (p<0.001). Health and economic implications of this and limitations of current food safety standards are discussed. Humans and animals in Kenya are chronically exposed to mycotoxin hazards that require constant surveillance and strict regulation.

scientific communication and education↗

bioRxiv2019

Seroprevalence of zoonotic diseases (leptospirosis and Japanese encephalitis) in swine in ten provinces of Vietnam: a Bayesian approach to estimate prevalence

BackgroundLeptospirosis is an important zoonotic disease with a global distribution, affecting a wide range of mammalian animals and humans. Japanese encephalitis (JE) virus is the major vector-borne zoonotic disease in the Asia-Pacific region. The main objective of this study was to evaluate the seroprevalence of serovar-specific Leptospira and JE in swine from 10 provinces in Vietnam.\n\nMethodsSamples were initially collected for swine influenza surveillance from March to April 2017 at large-scale farms (with at least 50 sows and/or 250 fattening pigs) with pigs that tested positive for influenza in the previous surveillance period (2015-16).\n\nFindingsA total of 2,000 sera samples were analyzed from 10 provinces. Overall, the seroprevalence of leptospirosis was 21.05% (95% CI: 19.28-22.90) using a cut-off titer of [≥] 1:100. The apparent prevalence of JE was 73.45% (95% CI: 71.46-75.37) while the true prevalence was slightly higher (74.46%, 95% credible interval: 73.73-86.41). We found a relatively high presence of leptospirosis and JE in pigs kept on large farms. Prevalence was comparable with other studies suggesting opportunistic testing of samples collected for other surveillance purposes can be a valuable tool to better understand and prevent the potential transmission of these zoonotic diseases from pigs to people in Vietnam.\n\nConclusionOur study provides evidence to veterinarians and animal health professionals for evidence-based practice such as diagnosis, vaccination and zoonotic control. Further investigation into the possible role of different domestic animals, wildlife species or environmental factors is needed to identify the potential risk factors and transmission routes in Vietnam.

epidemiology↗