Tesfaye Sisay Tessema

Seroepidemiology of Toxoplasma gondii infection in women of child-bearing age in central Ethiopia

BackgroundToxoplasma gondii infections during pregnancy can result in abortion or congenital defects. Prevalence and risk factors of toxoplasmosis in women of child-bearing age in Ethiopia are unknown. The current study was conducted with the objectives of estimating the seroprevalence and potential risk factors in acquiring T. gondii infection by women of child-bearing age in Central Ethiopia.MethodsA cross-sectional study was conducted from March 2011 to September 2011. Sera of 425 women were analyzed by indirect enzyme linked immunosorbent assay (ELISA). A questionnaire survey was administered for all study participants to gather information on risk factors.ResultsThe study revealed that anti- T. gondii IgG antibodies were detected in 81.4% of the samples of which 78.4% were positive for only IgG and 3.06% positive for both IgG and IgM antibodies. Seroprevalence of IgM antibodies to T. gondii (4.0%, 95% CI: 2.14, 5.86) was suggestive of recent infections. Of the 213 pregnant women 9 (4.2 %) were IgM reactive. Out of 17 potential risk factors investigated, univariate logistic regression showed significant association of T. gondii infection with study area, age, pregnancy status, raw vegetable consumption, source of water, presence of cats at home, contact with cats, HIV status and precaution during cats’ feces cleaning (P ≤ 0.05). The final logistic regression model revealed that: the probability of acquiring T. gondii infection by women of Debre-Zeit was 4.46 times (95% CI of adjusted odds ratio [aOR]: 1.67, 11.89; P =0.003) higher compared to women of Ambo, pregnant women were twice (95% CI aOR: 1.13, 3.59; P = 0.018) more likely to be seropositive than non-pregnant women and women who consume raw vegetable were at increased risk of infection (aOR = 2.21, 95% CI: 1.03, 4.78; P = 0.043) than women who didn’t consume.ConclusionThe seroprevalence of T. gondii infection in women of child-bearing age in Central Ethiopia is high. Study area, pregnancy and raw vegetable consumption are risk factors to acquire T. gondii infection. Educational program, antenatal screening of pregnant women and further epidemiological studies to uncover the economic and health impact of toxoplasmosis are suggested.

Pathology of Camel Tuberculosis and Molecular Characterization of Its Causative Agents in Pastoral Regions of Ethiopia

A cross sectional study was conducted on 906 apparently healthy camels slaughtered at Akaki and Metehara abattoirs to investigate the pathology of camel tuberculosis (TB) and characterize its causative agents using postmortem examination, mycobacteriological culturing, and multiplex polymerase chain reaction (PCR), region of difference-4 (RD4)-based PCR and spoligotyping. The prevalence of camel TB was 10.04% (91/906) on the basis of pathology and it was significantly higher in females (χ2 = 4.789; P = 0.029). The tropism of TB lesions was significantly different among the lymph nodes (χ2 = 22.697; P = 0.002) and lung lobes (χ2 = 17.901; P = 0.006). Mycobacterial growth was observed in 34% (31/91) of camels with grossly suspicious TB lesions. Upon further molecular characterization using multiplex PCR, 68% (21/31) of the colonies showed a positive signal for the genus Mycobacterium, of which two were confirmed Mycobacterium bovis (M. bovis) by RD4 deletion typing. Further characterization of the two M. bovis at strains level revealed that one of the strains was SB0133 while the other strain was new and had not been reported to the M. bovis database prior to this study. Hence, it has now been reported to the database, and designated as SB1953. In conclusion, the results of the present study have shown that the majority of camel TB lesions are caused by mycobacteria other than Mycobacterium tuberculosis complex. And hence further identification and characterization of these species would be useful towards the efforts made to control TB in camels.

Seroepidemiological study of caprine toxoplasmosis in East and West Shewa Zones, Oromia Regional State, Central Ethiopia.

Toxoplasmosis is a global zoonosis caused by Toxoplasma gondii, an intracellular apicomplexan parasite. The objectives of this study were to estimate the animal and flock level seroprevalence and risk factors associated with toxoplasmosis in goats of Central Ethiopia. In Ethiopia, goats are economically important animals used for meat and milk production. The study was cross-sectional and 927 blood samples from 187 goat flocks were collected to examine T. gondii specific IgG antibodies by enzyme linked immunosorbent assay (ELISA). A questionnaire was used to collect data on the potential risk factors. The study revealed flock and animal level seroprevalence of 58.3% (109/187; 95% confidence interval [CI]: 51.16, 65.42) and 19.7% (183/927; 95% CI: 17.17, 22.31), respectively. The likelihood of acquiring T. gondii infection was higher in semi-intensively managed goats (Odds ratio [OR]=2.48, 95% confidence interval [CI]: 1.14, 5.37; P=0.022) than in extensively managed goats, in females than in males (OR=1.84, 95% CI: 1.16, 2.92; P=0.010), in adults than in young animals (OR=2.00, 95% CI: 1.21, 3.28; P=0.006), in small than in large flocks (OR=2.03, 95% CI: 1.03, 3.98; P=0.040), in goats kept under sedentary (OR=2.81, 95% CI: 1.41, 5.59; P=0.003) and agropastoral farming system (OR=3.62, 95% CI: 1.83, 7.18; P<0.001) than pastoral farming system and in goats allowed to drink water from the tap than those drinking from river and stagnant water bodies (OR=9.25, 95% CI: 3.04, 28.15; P<0.001). Our study indicates that exposure of goats to oocysts of T. gondii is widespread. We recommend further studies to determine the genotype of the parasite, public health and economic impacts of toxoplasmosis and the role of raw goat meat and milk as a source of infection for consumers.

Seroepidemiological study of ovine toxoplasmosis in East and West Shewa Zones of Oromia Regional State, Central Ethiopia

BackgroundToxoplasmosis is a globally distributed zoonosis. Consumption of raw or undercooked meat, which is among the main risk factors for acquiring human infection, is a popular tradition in Ethiopia. However, studies on toxoplasmosis in food animals used for human consumption in Ethiopia are very scarce. Thus, the objectives of the present study were to estimate the seroprevalence and the risk factors of T. gondii infection in sheep in Ambo, Ada’a-Liben and Fentale districts of Central Ethiopia. Sera from 1130 sheep were analyzed for Toxoplasma gondii specific IgG antibodies using an indirect enzyme linked immunosorbent assay (ELISA) with the P30 antigen. A questionnaire was administered to assess potential risk factors for T. gondii seropositivity. Association of seroprevalence with potential risk factors related to altitude, host and farm characteristics were analyzed by univariable and multivariable logistic regression.ResultsOverall flock and animal level seroprevalences were 70.48% (160/227; 95% CI: 64.51, 76.46) and 31.59% (357/1130; 95% CI: 28.88, 34.31), respectively. The multivariable logistic regression model indicated that the probability of acquiring T. gondii was higher in sheep from highland (2300 – 3200 meters above sea level) [Odds ratio (OR) = 4.11, 95% confidence interval (CI): 2.65, 6.36; P < 0.001] and midland (OR = 4.54, 95% CI: 2.76, 7.49; P < 0.001) than from lowland (<1500 meters above sea level), in females than in males (OR = 1.60, 95% CI: 1.04, 2.43, P = 0.033), in adult than in young animals (OR = 2.93, 95% CI: 1.97, 4.35, P < 0.001), in small than in large flocks (OR = 3.34, 95% CI: 1.26, 8.86, P = 0.016), and in sheep that were given tap water (OR = 4.07, 95% CI: 1.07, 15.42, P = 0.039) and river water (OR = 4.18, 95% CI: 1.54, 11.35, P = 0.005) than in those that drunk water from mixed sources (i.e., river, well, lake and pond).ConclusionsThe high flock and animal level seroprevalence of toxoplasmosis in sheep is a good marker of the potential risk for human infections. Altitude, sex, age, flock size and source of water were identified as important risk factors to acquire the infection. Public education and awareness training are imperative in order to alleviate the danger posed to consumers. Further detailed studies to assess the impact of infections are warranted.

First report of Toxoplasma gondii in camels (Camelus dromedarius) in Ethiopia: bioassay and seroepidemiological investigation

BackgroundToxoplasmosis is a major public health concern in many countries of the world. A cross-sectional and follow up experimental study designs were used for seroepidemiological and bioassay studies, respectively from November 2012 to April 2013. The objectives were to estimate the seroprevalence of T. gondii infection, to assess risk factors and to isolate the parasite from camels in the Fentale district, Ethiopia. A direct agglutination test (DAT) and indirect enzyme linked immunosorbent assay (ELISA) kits were used to test camel sera. Hearts and tongues (each 25 g) from 31 seropositive camels were bioassayed in mice. Associations between seroprevalence and potential risk factors (collected using a questionnaire survey) were analyzed using logistic regression.ResultsAn overall T. gondii prevalence of 49.62% (220/455) by DAT and 40.49% (179/451) by indirect ELISA test were detected. Herd level seroprevalence of 96.77% (30/31) (95% CI: 83.30- 99.92) by DAT was recorded and it was significantly higher in areas where wild felids are present (P = 0.038). Multivariable logistic regression showed that the likelihood of acquiring T. gondii infection was significantly higher in camels in the Ilala pastoral association [PA] (82.26%) (Adjusted Odds ratio [aOR] = 10.8; P < 0.001) than camels in the Galcha PA (31.43%), in camels of ≥ 8 years old (56.52%; aOR = 1.88; P = 0,033) than camels of ≤ 4 years old (34.26%) and in areas where domestic cats are present (aOR = 4.16; P = 0.006). All camel owners were uneducated, handle aborted fetus with bare hands, and drink raw camel milk. DAT and ELISA tests had moderate agreement (Kappa = 0.41). Viable T. gondii were isolated from 16.13% (5/31) of DAT positive camels. One DAT positive but ELISA negative camel sample gave a cyst positive result.ConclusionsT. gondii infection of camels in the study district is widespread. Age, presence of domestic cats and study PA are independent predictors of T. gondii seropositivity. Isolation of viable parasites from edible tissues of camels and the very poor knowledge of pastoralists about toxoplasmosis suggest the need for prevention of toxoplasmosis through bio-security measures, education and further investigation to unravel the impact of camel toxoplasmosis deserves consideration.

Isolation and genotyping of viable Toxoplasma gondii from sheep and goats in Ethiopia destined for human consumption.

BackgroundToxoplasma gondii is an obligate intracellular protozoan parasite that infects humans and a broad spectrum of warm-blooded vertebrates. The present study was undertaken with the objectives of isolation and determining the genotypes of T. gondii strains from sheep and goats slaughtered in East and West Shewa Zones of Oromia Regional State, Central Ethiopia.MethodsHearts of 47 sheep and 44 goats that were seropositive in the Direct Agglutination Test (DAT) were bioassayed in mice. A multiplex PCR assay with 15 microsatellite markers was employed for genotyping of T. gondii isolates from sheep and goats.ResultsViable T. gondii were isolated from 47 (51.65%) animals, 27 sheep and 20 goats. Most isolates caused sub-clinical infections in mice, however, 2 sheep and 1 goat isolates were mouse-virulent, killing mice between 19–27 days post-inoculation. The success of T. gondii isolation in mice increased significantly (P = 0.0001) with higher DAT antibody titers in sheep and goats. Genotyping revealed that 29 (87.88%) of the 33 isolates were Type II, 3 (9.09%) were Type III and 1 (3.03%) was atypical. Three strains (one type II, one type III, and the atypical genotype) were virulent for mice.ConclusionsT. gondii tissue cysts in sheep and goats slaughtered for human consumption are widespread. This is the first report on isolation and genotyping of T. gondii from sheep and goats of Ethiopia.

Seroprevalence and risk factors of Toxoplasma gondii infection in sheep and goats slaughtered for human consumption in Central Ethiopia.

BackgroundToxoplasmosis is one of the most common parasitic zoonoses worldwide. Humans get infections with T. gondii after ingesting raw or undercooked meat or oocysts via contaminated soil, food or water; or congenitally by transplacental transmission of tachyzoites. The objectives of the present study were to estimate the seroprevalence and assess risk factors for T. gondii infection in sheep and goats slaughtered for human consumption in Central Ethiopia.MethodsA cross-sectional study was carried out from September, 2011 to November, 2012 in randomly selected small ruminants (n = 628). Direct Agglutination Test (DAT) was used to detect IgG antibodies specific to T. gondii. A titer of 1: 40 or 1: 4000 or both was considered indicative of T. gondii exposure. Logistic regression was used to assess potential risk factors.ResultsAn overall seroprevalence of 17.68% (111/628) (95% confidence interval [CI]:14.77 − 20.89) was detected. Twenty percent (61/305) seroprevalence (95% CI: 15.6 − 624.94) in sheep was found with a reciprocal end titers of 60 in fourteen, 180 in three, 540 in two, 1620 in five, 6000 in nine, 18000 in six, 54000 in eleven and 162000 in eleven. Similarly, seroprevalence of 15.48% (50/323) (95% CI:11.71 − 19.89) in goats was found with a reciprocal end titers of 60 in eighteen, 180 in five, 540 in three, 1620 in seven, 6000 in four, 18000 in four, 54000 in five and 162000 in four. Multivariable logistic regression analysis showed that the risk of T. gondii infection was significantly higher in adult sheep (adjusted Odd ratio (aOR) = 2.02, 95% CI: 1.10 − 3.70; P = 0.023) than in young sheep and in sheep sampled during the dry season (aOR = 4.19, 95% CI: 1.55 − 11.33, P = 0.005) than those sampled during wet season.ConclusionsThe seroprevalence of T. gondii infection in small ruminants slaughtered for human consumption in Central Ethiopia is high. Age and season are significant predictors of seropositivity in sheep. The study highlighted the importance of meat of small ruminants as a potential source of infection for humans. Prevention of the spread of the disease through farm biosecurity measures is essential.

A meta-analysis of the prevalence of Salmonella in food animals in Ethiopia.

BackgroundThe globalization of the food supply and the increased movements of people, animals and goods have increased the threat of Salmonella infections in several countries. The objective of this study was to estimate the prevalence of Salmonella in food animals in Ethiopia by using meta-analytical methods.ResultsThe prevalence of Salmonella in slaughtered cattle, sheep, goats and pigs were 7.07%, 8.41%, 9.01% and 43.81% respectively. The occurrence of Salmonella was significantly higher in pigs than in slaughtered true ruminants (p <0.001) but not significantly different between cattle, sheep and goats (p >0. 05). S. Mishmarhaemek, S. Infantis and S. Hadar were the predominant isolates in cattle, small ruminants and pigs respectively. S. Typhimurium was isolated from all host species.ConclusionsAll food animals are considerable reservoirs of Salmonella and pose a significant risk to public health. Safety measures in slaughter houses and butcheries and education of the public could reduce the risk of transmission of Salmonella from animals to humans.

Molecular epidemiology of fluoroquinolone resistant Salmonella in Africa: A systematic review and meta-analysis

Background Wide-ranging evidence on the occurrence of fluoroquinolone (FQ) resistance genetic determinants in African Salmonella strains is not available. The main objectives of this study were to assess the heterogeneity, estimate pooled proportions and describe the preponderance of FQ-resistance determinants in typhoidal and non-typhoidal Salmonella (NTS) isolates of Africa. Methods Genetic and phenotypic data on 6103 Salmonella isolates were considered. Meta- and frequency analyses were performed depending on the number of studies by category, number of isolates and risks of bias. A random effects model was used to assess heterogeneity and estimate pooled proportions. Relative and cumulative frequencies were calculated to describe the overall preponderance of FQ-resistance determinants in quinolone resistant isolates. Results The pooled proportion of gyrA mutants (Salmonella enterica serovar Typhi, Salmonella enterica serovar Typhimurium, and Salmonella enterica serovar Enteritidis) was estimated at 5.7% (95% Confidence interval (CI) = 2.6, 9.8; Tau squared (T2) = 0.1105), and was higher in S. Typhi than in S. Typhimurium (odds ratio (OR) = 3.3, 95%CI = 2, 5.7). The proportions of each of gyrB and parC mutants, and strains with Plasmid Mediated Quinolone Resistance genes (qnrA, qnrB and qnrS) were low (≤ 0.3%). Overall, 23 mutant serotypes were identified, and most strains had mutations at codons encoding Ser83 and Asp87 of gyrA (82%, 95%CI = 78, 86). Conclusions Mutations at gyrA appear to account for ciprofloxacin non-susceptibility in most clinical Salmonella strains in Africa. The estimates could be harnessed to develop a mismatch-amplification mutation-assay for the detection of FQ-resistant strains in Africa.

Testicular cytological profiles of apparently healthy male dromedary camels during rutting and non-rutting periods.

The aim of this study was to evaluate testicular cytological profiles of apparently healthy dromedary bulls during rutting and non-rutting periods. Pairs of testes from 26 (18 non-rutting and 8 rutting seasons) dromedary bulls 6-12 years old that were slaughtered at Akaki, Addis Ababa abattoir were sampled. A 21 gauge needle attached to 20mL syringe was used to collect Testicular Fine Needle Aspiration (TFNA) samples and five aspiration smears were prepared from each testis. A total of 312 slides (260 Testicular fine Needle Aspiration and 52 imprints) were examined. The mod ified May-Grunwald Giemsa (mMGG) technique and a light microscope were used to assess cellularity, morphology and quantification of the testicular. Sertoli and spermatogenic cells were identified and counted. The spermatic index (SI), Sertoli cell index (SEI) and the relationship between SI and SEI indexes (SSEI) were used to assess the ratio between mature spermatozoa and nursing cells. There were differences (P<0.05) between the rutting and non-rutting seasons among the spermatogenic and Sertoli cells. There were no differences between groups for primary spermatocyte numbers, early spermatid numbers and SSEI. There was no differences (P>0.05) between TFNA and imprint smear slides of the testicular cells except for Sertoli cell count and SEI. Filarial worm larvae were present on the TFNA smear slides of four animals. Imprint and TFNA smear slides had comparable cytological profiles in dromedary bulls and significant differences were observed between rutting and non-rutting periods.