Prevalence of porcine cysticercosis in Mbozi and Mbeya rural districts, Mbeya Tanzania

An epidemiological survey was conducted between November and December 2007 in 30 randomly selected villages and four slaughterslabs in Mbozi and Mbeya Rural districts, southern Tanzania, to determine the prevalence of porcine cysticercosis. Fifteen villages and three slaughterslabs were from Mbozi and fifteen villages and one slaughterslab were from Mbeya Rural. A total of 600 live pigs (300 in each district) of different sex and age categories were randomly selected from smallholder pig-keeping households and subjected to lingual examination and Antigen-ELISA tests. Postmortem examination was performed in pigs slaughtered in official slaughterslabs and local brew clubs. Questionnaire survey and direct observations were used to investigate potential factors related to transmission of T. solium. The overall prevalence of porcine cysticercosis in Mbozi district was 11.7% (95% CI = 8.5-15.8%) and 32% (95% CI: 27- 37.5%) based on lingual examination and Antigen-ELISA, respectively. In Mbeya Rural district, the prevalences were 6% (95% CI: 3.8-9.3%) and 30.7% (95% CI: 25.8- 36.1%), by lingual examination and Antigen-ELISA tests, respectively. The agreement between the two tests was poor (κ < 40%). There were no significant differences in the prevalence of porcine cysticercosis in different age and sex categories of pigs. None of the 805 pigs slaughtered at official slaughterslabs was infected with cysticercosis based on post-mortem inspection. However, of those slaughtered at local brew clubs, 8.2% (n=437) in Mbozi district and 10.8% (n=74) in Mbeya Rural were positive for cysticercosis. Potential risk factors for porcine cysticercosis in the districts included poor pig management, poor sanitary practices, lack of knowledge on the transmission of T. solium, and lack of meat inspection services. This study recommends educational campaigns in the study communities on the epidemiology of the disease, and subsequent revision of the current regulatory framework for pig trade and pork inspection to safeguard public health and improve livelihoods

Molecular epidemiology and antimicrobial resistance of thermophilic campylobacter infections in humans and animals in Tanzania

PhD ThesisMembers of the genus Campylobacter are known to cause more cases of human gastrointestinal illness than any other bacterium worldwide. The organisms exist as normal flora in the intestinal tracts of domestic and wild animals, more so in avian species. Humans acquire Campylobacter infections from contaminated animal products, particularly poultry meat, either directly or through cross-contamination of other food products. Human infections are mostly attributed to Campylobacter jejuni and C. coli, the former causing a larger proportion (85-90%) of all cases reported. In addition to infections, campylobacteriosis is also associated with the emerging threat of antimicrobial resistance as evidenced in isolates derived from different sources. An accurate picture of the epidemiology of infections caused by Campylobacter and other aetiological agents is lacking in developing countries due to the absence of regular surveillance programmes. Consequently the present study was conducted in Morogoro Municipality, Eastern Tanzania, to determine the molecular epidemiology and antimicrobial resistance of thermophilic Campylobacter isolates from humans and animals. Specific objectives were; 1) To establish the prevalence of thermophilic Campylobacter infections in humans and animals, 2) To determine the genetic relatedness of chicken and human derived thermophilic Campylobacter isolates using DNA-based typing methods, 3) To evaluate the antimicrobial resistance patterns in thermophilic Campylobacter isolates derived from humans and animals; and 4) To identify risk factors for thermophilic Campylobacter infections in humans. Stool samples were collected from 1195 human subjects; and fecal samples from 1511 farm animals, 466 laboratory animals and 112 wild birds (Indian house crows). Farm animals constituted chickens (n=1267), cattle (n=98), goats (n=81), sheep (n=57), horses (n=5) and camels (n=3); whereas laboratory animals were composed of guinea pigs (Cavia porcelllus, n= 30), mice (Mus musculus, n=160), rabbits (Oryctulagusiii cuniculus, n=34) and rats (Rattus rattus, n=242). The Cape Town protocol was used for isolation of thermophilic Campylobacter from stool and fecal samples. Campylobacter isolates were identified by phenotypic and molecular techniques. The isolates were tested for resistance against several antimicrobial agents using the disc diffusion method. Risk factors for human infections with thermophilic Campylobacter were determined in an unmatched case control study. Selected human and chicken derived Campylobacter jejuni isolates were genotyped using flagellin A gene sequencing. In humans the prevalence of thermophilic Campylobacter was 11.4% (n=1195). Symptomatic (12.9%) and young individuals (16.7%) were more infected than asymptomatic (6.7%) and adults (10%), respectively. Most (84.6%) of the isolates were C. jejuni and the remaining were C. coli; and the difference was statistically significant at p≤0.05. Isolates had highest resistance (95.6%) for colistin sulphate and lowest for ciprofloxacin (22.1%). Proportions of resistant isolates for other antibiotics (azithromycin, erythromycin, tetracycline, cephalethin, gentamycin, nalidixic acid, ampicillin, amoxycillin, norfloxacin and chloramphenicol) ranged from 44.1% to 89%. Human infections with thermophilic Campylobacter were associated with young age; and consumption of chicken meat, barbecue and pre-prepared salad. In avians, thermophilic Campylobacter spp. were isolated from 44.0% and 20.5% of the sampled chickens and crows respectively. The majority of isolates from both chickens (87.6%) and crows (56.5%) were C. jejuni and the remaining were C. coli. The observed difference in proportions of C. jejuni and C. coli isolates was statistically significant (p≤0.05) in chickens but not in house crows. Chicken isolates had highest resistance to Colistin sulphate whereas crow isolates showed highest resistance to azithromycin and erythromycin. Lowest resistance was observed for gentamycin and ciprofloxacin for crow and chicken isolates respectively. Among chicken isolates significantly high proportions of C. coli were resistant to gentamycin, cephalothin, tetracycline, colistin sulphate and chloramphenical. On the other hand a high proportion C. jejuni isolates were resistant toiv nalidixic acid. Crow derived C. jejuni had significantly higher resistance to nalidixic acid, cephalothin and ciprofloxacin than C. coli isolates from the same hosts. Among farm animals thermophilic Campylobacter were detected from 18 (31.6%) sheep and 3/5 (60%) of horses. Of the isolates 12 (57%) were C. jejuni; the remaining (43%) were C. coli. Of the laboratory animals 8 (26.7%) guinea pigs and 3 (1.2%) rats were colonized with Campylobacter. Four isolates from the guinea pigs were C. jejuni and the other 4 were C. coli. From the rats two isolates were C. jejuni and one was C. coli. The isolates showed high levels of antimicrobial resistance to erythromycin, norfloxacin colistin sulphate and nalidixic acid in ascending order; whereas low levels of resistance were observed for ciprofloxacin and gentamycin. Out of 55 sequenced isolates obtained from sporadic cases of human illness and different categories of chickens, nine different flaA types (7, 36, 41, 51, 61, 62, 64, 105 and 111) were detected. Both C. jejuni isolates from humans and chickens displayed a high degree of genetic diversity thereby suggesting weak clonality among the tested isolates. Genetic relatedness of some isolates from human and avian sources was however evident as on phylogenetic analysis some clusters contained both human and chicken C. jejuni isolates. The work contained in this thesis contributes significantly to the limited, available information on epidemiology and antimicrobial resistance of human and animal Campylobacter infections in Tanzania. For the first time the occurrence of Campylobacter infections in laboratory animals, antimicrobial resistance of human derived Campylobacter isolates, risk factors for human Campylobacter infections; and the population structure and relatedness of Campylobacter jejuni isolates from humans and chickens in the country are provided. The observed clusters containing isolates from human and avian sources confirm interspecies transmission of this zoonotic pathogen. Information on antimicrobial resistance of Campylobacter isolates derived from avian species in the country is also complemented. Control measures for colonization of animals and occurrence of infections in humans with this particular bacterium species arev warranted. Similarly strategies to stem emergency and spread of antimicrobial resistant Campylobacter strains should be put in place.Danish International Development Fun

Prevalence of porcine cysticercosis in Mbozi and Mbeya rural districts, Mbeya Tanzania

An epidemiological survey was conducted between November and December 2007 in 30 randomly selected villages and four slaughterslabs in Mbozi and Mbeya Rural districts, southern Tanzania, to determine the prevalence of porcine cysticercosis. Fifteen villages and three slaughterslabs were from Mbozi and fifteen villages and one slaughterslab were from Mbeya Rural. A total of 600 live pigs (300 in each district) of different sex and age categories were randomly selected from smallholder pig-keeping households and subjected to lingual examination and Antigen-ELISA tests. Postmortem examination was performed in pigs slaughtered in official slaughterslabs and local brew clubs. Questionnaire survey and direct observations were used to investigate potential factors related to transmission of T. solium. The overall prevalence of porcine cysticercosis in Mbozi district was 11.7% (95% CI = 8.5-15.8%) and 32% (95% CI: 27- 37.5%) based on lingual examination and Antigen-ELISA, respectively. In Mbeya Rural district, the prevalences were 6% (95% CI: 3.8-9.3%) and 30.7% (95% CI: 25.8- 36.1%), by lingual examination and Antigen-ELISA tests, respectively. The agreement between the two tests was poor (κ < 40%). There were no significant differences in the prevalence of porcine cysticercosis in different age and sex categories of pigs. None of the 805 pigs slaughtered at official slaughterslabs was infected with cysticercosis based on post-mortem inspection. However, of those slaughtered at local brew clubs, 8.2% (n=437) in Mbozi district and 10.8% (n=74) in Mbeya Rural were positive for cysticercosis. Potential risk factors for porcine cysticercosis in the districts included poor pig management, poor sanitary practices, lack of knowledge on the transmission of T. solium, and lack of meat inspection services. This study recommends educational campaigns in the study communities on the epidemiology of the disease, and subsequent revision of the current regulatory framework for pig trade and pork inspection to safeguard public health and improve livelihoods

Molecular epidemiology and antimicrobial resistance of thermophilic campylobacter infections in humans and animals in Tanzania

PhD ThesisMembers of the genus Campylobacter are known to cause more cases of human gastrointestinal illness than any other bacterium worldwide. The organisms exist as normal flora in the intestinal tracts of domestic and wild animals, more so in avian species. Humans acquire Campylobacter infections from contaminated animal products, particularly poultry meat, either directly or through cross-contamination of other food products. Human infections are mostly attributed to Campylobacter jejuni and C. coli, the former causing a larger proportion (85-90%) of all cases reported. In addition to infections, campylobacteriosis is also associated with the emerging threat of antimicrobial resistance as evidenced in isolates derived from different sources. An accurate picture of the epidemiology of infections caused by Campylobacter and other aetiological agents is lacking in developing countries due to the absence of regular surveillance programmes. Consequently the present study was conducted in Morogoro Municipality, Eastern Tanzania, to determine the molecular epidemiology and antimicrobial resistance of thermophilic Campylobacter isolates from humans and animals. Specific objectives were; 1) To establish the prevalence of thermophilic Campylobacter infections in humans and animals, 2) To determine the genetic relatedness of chicken and human derived thermophilic Campylobacter isolates using DNA-based typing methods, 3) To evaluate the antimicrobial resistance patterns in thermophilic Campylobacter isolates derived from humans and animals; and 4) To identify risk factors for thermophilic Campylobacter infections in humans. Stool samples were collected from 1195 human subjects; and fecal samples from 1511 farm animals, 466 laboratory animals and 112 wild birds (Indian house crows). Farm animals constituted chickens (n=1267), cattle (n=98), goats (n=81), sheep (n=57), horses (n=5) and camels (n=3); whereas laboratory animals were composed of guinea pigs (Cavia porcelllus, n= 30), mice (Mus musculus, n=160), rabbits (Oryctulagusiii cuniculus, n=34) and rats (Rattus rattus, n=242). The Cape Town protocol was used for isolation of thermophilic Campylobacter from stool and fecal samples. Campylobacter isolates were identified by phenotypic and molecular techniques. The isolates were tested for resistance against several antimicrobial agents using the disc diffusion method. Risk factors for human infections with thermophilic Campylobacter were determined in an unmatched case control study. Selected human and chicken derived Campylobacter jejuni isolates were genotyped using flagellin A gene sequencing. In humans the prevalence of thermophilic Campylobacter was 11.4% (n=1195). Symptomatic (12.9%) and young individuals (16.7%) were more infected than asymptomatic (6.7%) and adults (10%), respectively. Most (84.6%) of the isolates were C. jejuni and the remaining were C. coli; and the difference was statistically significant at p≤0.05. Isolates had highest resistance (95.6%) for colistin sulphate and lowest for ciprofloxacin (22.1%). Proportions of resistant isolates for other antibiotics (azithromycin, erythromycin, tetracycline, cephalethin, gentamycin, nalidixic acid, ampicillin, amoxycillin, norfloxacin and chloramphenicol) ranged from 44.1% to 89%. Human infections with thermophilic Campylobacter were associated with young age; and consumption of chicken meat, barbecue and pre-prepared salad. In avians, thermophilic Campylobacter spp. were isolated from 44.0% and 20.5% of the sampled chickens and crows respectively. The majority of isolates from both chickens (87.6%) and crows (56.5%) were C. jejuni and the remaining were C. coli. The observed difference in proportions of C. jejuni and C. coli isolates was statistically significant (p≤0.05) in chickens but not in house crows. Chicken isolates had highest resistance to Colistin sulphate whereas crow isolates showed highest resistance to azithromycin and erythromycin. Lowest resistance was observed for gentamycin and ciprofloxacin for crow and chicken isolates respectively. Among chicken isolates significantly high proportions of C. coli were resistant to gentamycin, cephalothin, tetracycline, colistin sulphate and chloramphenical. On the other hand a high proportion C. jejuni isolates were resistant toiv nalidixic acid. Crow derived C. jejuni had significantly higher resistance to nalidixic acid, cephalothin and ciprofloxacin than C. coli isolates from the same hosts. Among farm animals thermophilic Campylobacter were detected from 18 (31.6%) sheep and 3/5 (60%) of horses. Of the isolates 12 (57%) were C. jejuni; the remaining (43%) were C. coli. Of the laboratory animals 8 (26.7%) guinea pigs and 3 (1.2%) rats were colonized with Campylobacter. Four isolates from the guinea pigs were C. jejuni and the other 4 were C. coli. From the rats two isolates were C. jejuni and one was C. coli. The isolates showed high levels of antimicrobial resistance to erythromycin, norfloxacin colistin sulphate and nalidixic acid in ascending order; whereas low levels of resistance were observed for ciprofloxacin and gentamycin. Out of 55 sequenced isolates obtained from sporadic cases of human illness and different categories of chickens, nine different flaA types (7, 36, 41, 51, 61, 62, 64, 105 and 111) were detected. Both C. jejuni isolates from humans and chickens displayed a high degree of genetic diversity thereby suggesting weak clonality among the tested isolates. Genetic relatedness of some isolates from human and avian sources was however evident as on phylogenetic analysis some clusters contained both human and chicken C. jejuni isolates. The work contained in this thesis contributes significantly to the limited, available information on epidemiology and antimicrobial resistance of human and animal Campylobacter infections in Tanzania. For the first time the occurrence of Campylobacter infections in laboratory animals, antimicrobial resistance of human derived Campylobacter isolates, risk factors for human Campylobacter infections; and the population structure and relatedness of Campylobacter jejuni isolates from humans and chickens in the country are provided. The observed clusters containing isolates from human and avian sources confirm interspecies transmission of this zoonotic pathogen. Information on antimicrobial resistance of Campylobacter isolates derived from avian species in the country is also complemented. Control measures for colonization of animals and occurrence of infections in humans with this particular bacterium species arev warranted. Similarly strategies to stem emergency and spread of antimicrobial resistant Campylobacter strains should be put in place.Danish International Development Fun

Occurrence and Determination of Antimicrobial Resistant Escherichia coli Isolates in Fish and Vegetables as Indicator Organism of Faecal Contamination in Dar es Salaam, Tanzania

Escherichia coli such as E. coli O157:H7, a non-sorbitol-fermenting (NSF) E. coli, is an essential human pathogen among other common zoonotic pathogens carried by animals especially cattle. They are discharged through cattle faeces into the environment. With the increasing practice of urban farming, livestock manure is used as organic fertiliser in either fish ponds or vegetable gardens. This practice increases the risk of transmission of such pathogens to humans. This study aimed at determining the occurrence, antimicrobial resistance profiles, and genetic relatedness of E. coli isolates from manure, vegetables, and fish. Microbiological standard methods were used to isolate and identify E. coli isolates from manure, vegetable, and fish samples. Confirmed isolates on biochemical tests were tested for resistance against six antibiotics using the disc diffusion method. Enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) typing method was used to generate fingerprints and determine the genetic relatedness of the E. coli isolates. Of 156 samples including 89 manure, 53 vegetables, and 16 fish, 36 (23.1%) samples were positive for E. coli from where a total of 48 E. coli different isolates were recovered that were subjected to antimicrobial susceptibility testing and genetic relatedness. Of these isolates, 25 (52.1%) were resistant to at least one antimicrobial agent and 12 (48.0%) showed multidrug resistance. ERIC-PCR profiles of E. coli isolates from manure, vegetables, and fish showed genetic diversity with genetic relatedness ranging from 74.5% to 100%. Nine phylogenetic clusters (I–IX) determined at 90% threshold level of genetic relatedness were identified among the isolates. This study determined the occurrence, antimicrobial resistant patterns, and genetic diversity of antimicrobial-resistant E. coli isolates from different sources. This study showed the potential of microbial health risk to humans through contamination, and hence, it is necessary to monitor and improve husbandry practices in urban farming