Marc K. Kouam

Seroprevalence of equine piroplasms and host-related factors associated with infection in Greece.

Serum samples were collected from a total of 544 equids that included 524 horses, 13 mules, and 7 ponies from various regions of mainland Greece and were examined by competitive-inhibition ELISA (cELISA) to evaluate the level of exposure of Greek equids to Theileria (Babesia) equi and/or Babesia caballi, the causative agents of piroplasmosis. Association between seropositivity and host-related factors of species, gender, age, origin, activity and location were investigated. The overall seroprevalence was 11.6% (9.1-14.6%) with 95% confidence limit. The seroprevalence for T. equi and B. caballi was found to be 11% (8.6-14%) and 2.2% (1.2-3.9%), respectively. The animal-related factors significantly linked with seropositivity were the species, activities of farming, racing, recreation, and geographic location in Attica, Macedonia, Peloponnese and Thessaly region (p<0.05). The relative risks for the presence of T. equi, B. caballi and mixed infection in mules compared to horses was 8.39, 33.58 and 40.31, respectively. The infection level for T. equi, B. caballi and mixed infection were significantly higher in farm equids than in racing equids (p<0.05). Also, the rate of infection of T. equi was higher in farm equids than recreational equids (p<0.05). The relative risk of T. equi infection between farming equids and equids used only for recreation activity was 3.25-1, while the relative risk of B. caballi infection was 0.14-1 for racing animals relative to recreation animals. The region with the highest level of infection to both parasites was Thessaly (38.8% T. equi and 6.1% B. caballi), followed by Peloponnese (10.4% T. equi and 3.9% B. caballi), Attica region (8.3% T. equi and 0.6% B. caballi) and finally Macedonia the region with the lowest prevalence (6.6% T. equi and 4.4% B. caballi). A higher seroprevalence rate was found among local animals compared to imported equids, indicating that equine piroplasm infection is enzootic in Greece. T. equi seroprevalence was significantly different and higher among increasing age groups of equids, suggesting persistent infections or lower transmission levels whereby animals may need to be exposed longer before acquiring the infection. Competent tick vectors Rhipicephalus bursa and Rhipicephalus sanguineus for the transmission of equine piroplasmosis were recovered from horses and dogs, respectively.

A seroepidemiological study of exposure to Toxoplasma, Leishmania, Echinococcus and Trichinella in equids in Greece and analysis of risk factors.

The role of horses in the transmission of parasitic zoonoses either as a source of infection to vectors or through contamination of definitive hosts is gaining importance worldwide. For this reason sera from 773 equids including 753 horses, 13 mules and seven ponies in four regions of Greece were investigated by ELISA for the presence of IgG antibodies against Toxoplasma, Leishmania, Echinococcus and Trichinella. Anti-Toxoplasma antibodies were detected in all regions with an overall prevalence of 1.8%. In contrast, antibodies to Leishmania, Echinococcus, and Trichinella were present only in horses from the equestrian centre located in Attica region, but the status of Trichinella could not be confirmed. The seroprevalence of infection was 0.3% for Leishmania, 0.1% for Echinococcus and 0.1% for Trichinella. Only one horse was positive with a mixed infection of Toxoplasma, Leishmania and Trichinella. The following host characteristics were investigated for any significant effects on the prevalence of Toxoplasma infection: gender, age, species, origin of birth, activity, and location. The type of activity (p<0.05) and location (p<0.01) of the animals were found to be significant risk factors for Toxoplasma infection. The relative risk (RR) for Toxoplasma infection comparing the regions of Peloponnese and Thessaly to Attica were 6.92 and 6.78, respectively. Due to the very low prevalence of Echinococcus, Leishmania, and Trichinella infections, the associated risk factors were not analysed. The low seroprevalences observed suggest that the risk of infection from equids to people is very low, especially when consumption of horse meat is uncommon in this country.

Geographic distribution modelling for ruminant liver flukes (Fasciola hepatica) in south-eastern Europe.

Maximum entropy ecological niche modelling was utilised to predict the geographic range for fluke genotypes and haplotypes in south-eastern Europe, using the Maxent program. The lowest (0.832) and the highest (0.947) area under the curve values were observed in the models for the haplotypes CtCmt1 and CtCmt2.2, respectively. Precipitation and temperature contribute equally to model building of the genotypes based on the 28S rDNA gene. In regard to the mtDNA gene region, precipitation is the most important factor in modelling the CtCmt1 haplotype range, while temperature appears to be the most important factor in modelling the CtCmt2.1 and CtCmt2.2 haplotype ranges. The highest level of probability for the geographic distribution of Fasciola hepatica genotypes and haplotypes covered the regions of southern Bulgaria and central and northern Greece which contain a high concentration of potential ruminant hosts.

Seroprevalence and risk factors associated with zoonotic parasitic infections in small ruminants in the Greek temperate environment

A cross-sectional serological study was carried out to screen the sheep and goat population of Thessaly, Greece for evidence of infection with Toxoplasma, Toxocara, Leishmania, and Echinococcus and to determine the risk factors related to herd characteristics, herd management practices, farmer status, and the bioclimatic variables associated with these zoonotic parasitic infections. A total of 540 sheep and goat serum samples were examined. The seroprevalence of infection in all examined animals was 24.5% for Toxoplasma, 32% for Toxocara, 0% for Leishmania and 85.9% for Echinococcus. The final logistic regression model showed that the species of small ruminant, herd size, anthelmintic treatment, class of anthelmintic treatment, grazing with other herds, educational level of farmer, elevation of farm location, and generalized land cover were associated with Toxoplasma gondii infections, while the species of small ruminant, farm type, anthelmintic treatment, class of anthelmintic treatment, rotation of grazing, age of farmer, elevation of farm location, and generalized land cover were associated with Toxocara canis infections. Antibodies to T. gondii were detected in 102 (28.3%) of 360 sheep and in 30 (16.8%) of 179 goats. Animals in small flocks (150-300 animals) had an approximately 0.42-fold lower risk of having positive cases of T. gondii among animals compared with large flocks (>300 animals). Antibodies to T. canis were found in 155 (42.9%) of 361 sheep and 18 (10.1%) of 179 goats. The later finding constitutes the first report of seropositive goats to Toxocara. The risk of positivity for T. canis was 7.71-fold higher in sheep than in goats. Geographically, animals from plain areas had 2.9 and 2.01-fold higher risk of having positive cases of T. gondii and T. canis respectively. The significant bioclimatic variables (p<0.05) associated with the occurrence locations of T. gondii infection were related to higher temperature, lower precipitation, and lower elevation compared to the absence locations of T. gondii. The significant bioclimatic variables (p<0.05) associated with occurrence locations of T. canis infection were related to lower temperature and higher precipitation compared to absence locations of T. canis. These findings are useful to formulate appropriate control strategies for zoonotic parasites of sheep and goats in Greece and other areas with similar climatic conditions.

Genetic diversity of equine piroplasms in Greece with a note on speciation within Theileria genotypes (T. equi and T. equi-like)

Equine piroplasms in Greece were studied using the reverse line blot hybridization (RLB) assay. Three genotypes consisting of two Theileria (T. equi and T. equi-like) and one Babesia (B. caballi-like) were identified. Of 787 samples tested, 371 (47.14%) hybridised to catchall probe (probe specifically designed to capture any piroplasm species present in a sample), 346 (43.96%) to T. equi probe, 364 (46.25%) to T. equi-like probe, 0 (0%) to B. caballi probe and 3 (0.38%) to B. caballi-like probe. Seven samples gave faint signals with the catchall probe only, indicating the presence of known or unknown piroplasm species, or a novel genotype or a known genotype occurring at a very low level of parasitemia. A partial sequence (509 bp) of the V4 region of the 18S rRNA gene of a T. equi-like isolate showed only 99% similarity with the reference T. equi-like isolates from Northern Spain from which the detecting probe used in the present study was designed but showed 100% similarity with the T. equi-like variants from Southern Spain. This indicated a noticeable degree of polymorphism within the population of T. equi-like. No unusual parasites previously reported in horses, such as B. canis canis and B. bovis were detected in this study. The values of the bioclimatic variables were very similar between the geographic locations for T. equi and T. equi-like genotypes, suggesting the two are not yet different species as hypothesized by some authors but are possibly undergoing a speciation process within Theileria genotypes. Both T. equi and T. equi-like were found in predominantly forest type land cover.

Risk factors and geospatial modelling for the presence of Fasciola hepatica infection in sheep and goat farms in the Greek temperate Mediterranean environment.

Risk factors related to herd and farmer status, farm and pasture management, and environmental factors derived by satellite data were examined for their association with the prevalence of F. hepatica in sheep and goat farms in Thessaly, Greece. Twelve farms (16.2%) and 58 farms (78.4%) of 74 had evidence of infection using coproantigen and serology respectively. The average normalized difference vegetation index (NDVI) of farm location for 12 months before sampling was the most significant environmental risk factor for F. hepatica infection based on high seropositivity. The risk of infection increased by 1% when the value of NDVI increased by 0.01 degree. A geospatial map was constructed to show the relative risk (RR) of Fasciola infection in sheep and goat farms in Thessaly. In addition, geospatial maps of the model-based predicted RR for the presence of Fasciola infection in farms in Thessaly and the entire area of Greece were constructed from the developed model based on NDVI. In conclusion, this study demonstrated that Thessaly should be regarded as an endemic region for Fasciola infection and it represents the first prediction model of Fasciola infection in small ruminants in the Mediterranean basin.

Geographic distribution modeling and spatial cluster analysis for equine piroplasms in Greece

Maximum entropy ecological niche modeling and spatial scan statistic were utilized to predict the geographic range and to investigate clusters of infections for equine piroplasms in Greece, using the Maxent and SaTScan programs, respectively. The eastern half of the country represented the culminating area with high probabilities (p>0.75) of presence of equine piroplasms and encompassed most regions with high concentration of equid host populations. The most important environmental factor that contributed to the ecological niche modeling was land cover followed by temperature. Significant clusters (p<0.0001) were detected for Babesia caballi and Theileria equi infections in North and Central regions of Greece, respectively, which have significant equine populations. Maximum entropy ecological niche modeling and spatial scan statistic have proved to be useful tools for the surveillance of animal diseases.

Impact of repeated ivermectin treatments against onchocerciasis on the transmission of loiasis: an entomologic evaluation in central Cameroon

BackgroundAnnual community-directed treatment with ivermectin (CDTI) have been carried out since 1999 in the Lekie division (central region of Cameroon where most cases of Loa-related post ivermectin severe adverse events were reported) as part of the joined activities of the African Programme for Onchocerciasis Control (APOC) and Mectizan® Donation Program (MDP). As large-scale administration of ivermetine was demonstrated to be an efficient means to control loiasis transmission, it was hypothesized that CDTI would have lowered or halted the transmission of Loa loa in the Lekie division after 13 years of annual drug administration, indicating a possible reduction in the occurrence of Loa-related post-ivermectin severe adverse events.MethodsA 4-month entomologic study was carried out from March to June 2012 in the Lekie division to evaluate the impact of 13 years of CDTI on the transmission of L. loa whose baseline data were recorded in 1999–2000.ResultsThere was a significant reduction in the infection rate for Chrysops silacea and C. dimidiata from 6.8 and 9% in 1999–2000 to 3 and 3.6% in 2012, respectively. The differences in the infective rate (IR) (percentage of flies harboring head L3 larvae), potential infective rate (PIR) (percentage of flies bearing L3 larvae), mean head L3 larvae load (MHL3) (average L3 per infective fly) and mean fly L3 larvae load (MFL3) (average L3 per potentially infective fly) for both C. silacea and C. dimidiata were not significantly different between the two investigation periods. The biting density (BD) was almost three-fold higher in 2012 for C. silacea but not for C. dimidiata. The transmission potential (TP) which is a function of the BD, was higher in the present study than in the baseline investigation for each species.ConclusionThe infection rate remaining high, the high TP and the stability observed in the IR, PIR, MHL3 and MFL3 after 13 years of CDTI suggest that transmission of L. loa is still active. This is an indication that the risk of occurrence of severe adverse events such as fatal encephalopathies is still present, especially for heavily microfilaria-loaded people taken ivermectin for the first time.

Geographical distribution modelling for Neospora caninum and Coxiella burnetii infections in dairy cattle farms in northeastern Spain

Maximum entropy ecological niche modelling and spatial scan statistic were utilized to predict the geographical range and to investigate clusters of infections for Neospora caninum and Coxiella burnetii in dairy cattle farms in Catalonia, northeastern Spain, using the Maxent and SaTScan programs, respectively. The geographical distribution of Neospora and Coxiella with the highest level of probability (P > 0·60) covers central Catalonia and spreads towards northeastern Catalonia which contains a high concentration of dairy cattle farms. The most important environmental factor that contributed to the ecological niche modelling was precipitation of driest month followed by elevation. Significant clusters (P < 0·001) were detected for Neospora and Coxiella infections in the western and eastern regions of Catalonia, respectively.

Survey of gastrointestinal parasitic infections of beef cattle in regions under Mediterranean weather in Greece

Gastrointestinal (GI) parasitic infections of beef cattle were investigated in 15 farms from 3 different regions of Greece, characterized by temperate Mediterranean climate, during two years. A total of 262 faecal samples were collected. Helminth eggs were detected in 42 (16%) samples. Strongyle-type eggs were found in 28 (10.7%) samples, Strongyloides spp. and Toxocara spp. eggs in 8 (3.1%) samples each, and Capillaria spp. and Moniezia spp. eggs in 1 (0.4%) sample each. Coccidian oocysts were found in 123 (46.9%) samples. A logistic regression model showed that the age of animals, the number of employees, and the region of animals were associated with coccidian infections. There was almost a four-fold increase in the risk of coccidian infections in calves less than 12 months old compared with animals that were more than 36 months old (p<0.05). The risk of coccidian infections was 0.07, 0.18 and 0.27-fold lower for farms with 1, 2 and 3 employees respectively compared to farms with 4 employees; farms with less than 4 employees had a protective effect (p<0.05 in all cases). Almost a four-fold increased risk of coccidian infections was shown for animals from Epirus compared with those from Thessaly (p<0.05). These findings are useful to formulate appropriate control strategies for coccidian parasites of beef cattle in Greece and other areas with similar climatic conditions.