The role of Escherichia coli in the etiology of piglet diarrhea in selected pig producing districts of central Uganda

Background: Pig production in Uganda is highly constrained by rampant piglet mortalities with diarrhea being a key feature. The present study was conducted to determine possible involvement of Escherichia coli (E. coli) as agents of diarrhea in piglets and elucidate the factors for their spread and virulence, towards development of mitigation strategies in the smallholder pig value chains in Uganda. Methodology: This was a cross-sectional study carried out from January to August 2020 on pre- and post-weaned piglets from households in Kayunga and Mityana districts of Central Uganda, selected by snowballing method to redundancy. Data about herd management and risk factors for colibacillosis were collected from selected farmers in the two districts. A total of 179 faecal samples were collected from randomly selected neonatal and pre-weaning piglets for bacteriological isolation of Escherichia coli. Virulence (enterotoxin and fimbrial) genes from the isolates were detected by multiplex polymerase chain reaction (PCR) assay. Results: From the 179 faecal samples, a total of 158 (88.3%) E. coli isolates were obtained. Virulence gene markers were detected in 18.4% (29/158) of the isolates. Among the investigated genes encoding for enterotoxin production, STb was the most prevalent (16/158, 10.13%), followed by STa (12/158, 7.59%), while gene for LT was not detected. The gene coding for F4 adhesin was the only one detected while F18 adhesin was not detected from the isolates. On multiple logistic regression analysis, only tertiary educational level (OR=0.141; 95% CI=0.30-0.666; p=0.013) and infrequent use of antibiotics (OR=0.231, 95% CI=0.062-0.859; p=0.029) among the farmers, were the two factors significantly protective of the piglets from diarrhoea. Conclusion: This study reports a high prevalence of enterotoxin gene markers among E. coli isolates in piglets and revealed the potential role of these bacteria in the aetiology of piglet diarrhoea and mortalities in Uganda. Additionally, this study identified risk factors that can be useful in formulating treatment and control strategies of infection caused by these bacteria. Further studies are needed to identify more adhesins these E. coli isolates employ for intestinal colonization, a step that will help inform vaccine development.   French title: Le rôle d'Escherichia coli dans l'étiologie de la diarrhée des porcelets dans certains districts producteurs de porcs du centre de l'Ouganda   Contexte: La production porcine en Ouganda est fortement limitée par la mortalité généralisée des porcelets, la diarrhée étant une caractéristique clé. La présente étude a été menée pour déterminer l'implication possible Escherichia coli piglet diarrhea in Uganda  d'Escherichia coli (E. coli) en tant qu'agents de diarrhée chez les porcelets et élucider les facteurs de leur propagation et de leur virulence, vers le développement de stratégies d'atténuation dans les chaînes de valeur des petits producteurs de porcs en Ouganda. Méthodologie: Il s'agit d'une étude transversale réalisée de janvier à août 2020 sur des porcelets pré- et post-sevrés issus de ménages des districts de Kayunga et Mityana du centre de l'Ouganda, sélectionnés par la méthode boule de neige jusqu'à la redondance. Les données sur la gestion du troupeau et les facteurs de risque de colibacillose ont été recueillies auprès d'éleveurs sélectionnés dans les deux districts. Au total, 179 échantillons de matières fécales ont été prélevés sur des porcelets néonatals et en pré-sevrage sélectionnés au hasard pour l'isolement bactériologique d'Escherichia coli. Les gènes de virulence (entérotoxine et fimbrial) des isolats ont été détectés par une amplification en chaîne par polymérase (PCR) multiplex. Résultats: À partir des 179 échantillons de matières fécales, un total de 158 (88,3%) isolats d'E. coli ont été obtenus. Des marqueurs du gène de virulence ont été détectés dans 18,4% (29/158) des isolats. Parmi les gènes étudiés codant pour la production d'entérotoxines, STb était le plus répandu (16/158, 10,13%), suivi de STa (12/158, 7,59%), tandis que le gène de la LT n'a pas été détecté. Le gène codant pour l'adhésine F4 était le seul détecté alors que l'adhésine F18 n'a pas été détectée dans les isolats. Sur l'analyse de régression logistique multiple, seul le niveau d'enseignement supérieur (OR=0,141; IC à 95%=0,30-0,666; p=0,013) et l'utilisation peu fréquente d'antibiotiques (OR=0,231, IC à 95 %=0,062-0,859; p=0,029) parmi les éleveurs, étaient les deux facteurs de protection significative des porcelets contre la diarrhée. Conclusion: Cette étude rapporte une prévalence élevée de marqueurs génétiques d'entérotoxines parmi les isolats d'E. coli chez les porcelets et a révélé le rôle potentiel de ces bactéries dans l'étiologie de la diarrhée et de la mortalité des porcelets en Ouganda. De plus, cette étude a identifié des facteurs de risque qui peuvent être utiles dans la formulation de stratégies de traitement et de contrôle de l'infection causée par ces bactéries. D'autres études sont nécessaires pour identifier plus d'adhésines que ces isolats d'E. coli utilisent pour la colonisation intestinale, une étape qui aidera à éclairer le développement de vaccins

Molecular characterization of African swine fever virus in apparently healthy domestic pigs in Uganda

African swine fever (ASF) is a highly lethal and economically significant disease of domestic pigs in Uganda where outbreaks regularly occur. There is neither a vaccine nor treatment available for ASF control. Twenty two African swine fever virus (ASFV) genotypes (I - XXII) have been identified based on partial sequencing of the C-terminus of the major capsid protein p72 encoded by the B646L gene. The majority of previously characterized Ugandan ASFV strains belong to genotype IX. The major aim of the current study was to determine the ASFV genotypes among asymptomatic slaughter pigs at Wambizi slaughterhouse and in some parts of the country where surveillance was done. Three discrete regions of the ASFV were analysed in the genomes of viruses detected in asymptomatic domestic pigs. The analysis was conducted by genotyping based on sequence data from three single copy ASFV genes. The E183L gene encoding the structural protein P54 and part of the gene encoding the p72 protein were used to delineate genotypes, before intra-genotypic resolution of viral relationships by analysis of tetramer amino acid repeats within the hypervariable central variable region (CVR) of the B602L gene. All the ASF viruses obtained from this study clustered with previous viruses in genotype IX based on analysis of the p72 and P54 genes. Analysis of the CVR gene grouped the viruses in three different subgroups; 13, 23 and 25. Only one genotype is circulating in Uganda among asymptomatic domestic pigs and it is the same virus causing outbreaks in the country and parts of neighbouring Kenya.Keywords: African swine fever virus, asymptomatic, slaughterhouse, P54, p72, CVR gene, genotypesAfrican Journal of Biotechnology, Vol 13(25)2491-249

Haematological, biochemical and clinical changes in domestic pigs experimentally infected with african swine fever virus Isolates from Uganda

African swine fever (ASF) is a highly contagious often fatal viral disease of pigs caused by asfivirus. The disease causes marked leucopaenia, depletion of lymphocytes in the lymphoid tissues, changes in biochemical parameters, haemorrhages and necrosis in multiple organs of the infected pigs. We studied the pathogenic effect of three different Ugandan ASF virus (ASFV) isolates on twelve infected and six uninfected pigs. Each pig in the infected group was inoculated per os with 2 mls of ASFV culture solution containing 1X 108 H.A.D.U/ml of the viral culture solution while the control group were given 2 mls of uninfected porcine alveolar macrophages culture per-os. Clinical parameters were monitored daily and blood samples collected for leucocytes count and biochemical tests. In the present study, the incubation period of the disease ranged from 7 - 15 days and in average the clinical disease lasted for 5 days. On the eighth day post infection, all test pigs had significant leucopaenia (p = 0.000) and number of lymphocytes reduced significantly (p =0.001,). Band neutrophils progressively increased in number as the disease progressed, however when the changes in mean band neutrophils in the three groups were compared it was not statistically significant (p= 0.52). There were no significant variations in the mean basophils and eosinophil counts in all experimental groups during study period (p = 0.30 and p = 0.32 respectively). Nevertheless, mean monocytes counts significantly increased in infected pigs (p = 0.01), while in uninfected group there was no significant variation in the mean monocytes counts. The majority of the pigs, 83.3% (n = 10) in the test groups had elevated levels of gamma-glutamyl transferase (GGT). The Level of Alanine Amino Transferase (ALT) at 8 days post infection was elevated in all infected pigs in the three groups. In 66.7% (n = 8) infected pigs, Albumin (ALB) levels were elevated in the serum samples above the normal range of 18 – 33 g/l. The levels of other biochemicals in the serum samples such as Creatine kinase (CK), Creatinine (CREA), and Alkaline Phosphatase (ALKP) remained within the normal range (50- 3531 μ/L, 44 -186μmol/L, 92 - 294 μ/L, respectively). We concluded that ASF causes significant deviation in leucocytes counts, increased levels of GGT, ALT and ALB and clinical parameters in pigs infected with Ugandan isolates of ASF virus.Key words: African swine fever (ASF), Domestic pigs Haematological, biochemical and clinical parameter

Haematological, biochemical and clinical changes in domestic pigs experimentally infected with african swine fever virus Isolates from Uganda

African swine fever (ASF) is a highly contagious often fatal viral disease of pigs caused by asfivirus. The disease causes marked leucopaenia, depletion of lymphocytes in the lymphoid tissues, changes in biochemical parameters, haemorrhages and necrosis in multiple organs of the infected pigs. We studied the pathogenic effect of three different Ugandan ASF virus (ASFV) isolates on twelve infected and six uninfected pigs. Each pig in the infected group was inoculated per os with 2 mls of ASFV culture solution containing 1X 108 H.A.D.U/ml of the viral culture solution while the control group were given 2 mls of uninfected porcine alveolar macrophages culture per-os. Clinical parameters were monitored daily and blood samples collected for leucocytes count and biochemical tests. In the present study, the incubation period of the disease ranged from 7 - 15 days and in average the clinical disease lasted for 5 days. On the eighth day post infection, all test pigs had significant leucopaenia (p = 0.000) and number of lymphocytes reduced significantly (p =0.001,). Band neutrophils progressively increased in number as the disease progressed, however when the changes in mean band neutrophils in the three groups were compared it was not statistically significant (p= 0.52). There were no significant variations in the mean basophils and eosinophil counts in all experimental groups during study period (p = 0.30 and p = 0.32 respectively). Nevertheless, mean monocytes counts significantly increased in infected pigs (p = 0.01), while in uninfected group there was no significant variation in the mean monocytes counts. The majority of the pigs, 83.3% (n = 10) in the test groups had elevated levels of gamma-glutamyl transferase (GGT). The Level of Alanine Amino Transferase (ALT) at 8 days post infection was elevated in all infected pigs in the three groups. In 66.7% (n = 8) infected pigs, Albumin (ALB) levels were elevated in the serum samples above the normal range of 18 – 33 g/l. The levels of other biochemicals in the serum samples such as Creatine kinase (CK), Creatinine (CREA), and Alkaline Phosphatase (ALKP) remained within the normal range (50- 3531 μ/L, 44 -186μmol/L, 92 - 294 μ/L, respectively). We concluded that ASF causes significant deviation in leucocytes counts, increased levels of GGT, ALT and ALB and clinical parameters in pigs infected with Ugandan isolates of ASF virus.Key words: African swine fever (ASF), Domestic pigs Haematological, biochemical and clinical parameter

Retrospective study on cattle and poultry diseases in Uganda

Cattle and poultry enterprises are among the major contributors to food security and socioeconomic empowerment of households in Uganda. However, various diseases constrain their productivity. A two-year retrospective study between April 2012 and March 2014 was conducted using records for cattle and poultry diseases diagnosed at the Central Diagnostic Laboratory (CDL) to determine prevalent diseases in Uganda. The laboratory received 836 samples from poultry (36.3%) and cattle (63.7%). Of the 836 samples, 47.5% had a definitive diagnosis of disease causation. Most of the cattle and poultry diseases diagnosed were protozoan diseases (39.3%) followed by bacterial (21.4%), viral (17.1%), helminthiasis (11.1%), nutritional diseases (4%) and others (7.1%). For poultry, viral diseases (29.5%) and protozoan diseases (27.1%) especially newcastle disease (44.3%) and coccidiosis (100%) respectively, were the most diagnosed. While for cattle, hemo-protozoan parasites (52.1%) were the most prevalent, of which 92.9% were east coast fever infection. Bacterial infection (20.5%) in cattle were the second most diagnosed diseases and mastitis was the most diagnosed (46.2%). In summary, coccidioisis, collibacillosis, newcastle disease, gumboro disease, and avian helminthiasis were the most prevalent poultry diseases while in cattle, east coast fever, helminthiasis, mastitis, brucellosis and rabies were the most frequently diagnosed diseases. This study has identified the major diseases that hinder poultry and cattle production in Uganda. The data generated by CDL could be used for surveillance, monitoring and designing strategic interventions for control of poultry and cattle diseases in Uganda. Keywords: Coccidiosis, Collibacillosis, East coast fever, Mastitis, Newcastle disease, Rabie