Vaccination is an important disease prevention and control measure; however, vaccine adoption by livestock farmers in Tanzania is still low. This cross-sectional study examined the challenges to vaccine use faced by livestock owners and animal health professionals (AHPs) in Tanzania. A questionnaire was administered to 216 households that kept small ruminants and poultry and 19 AHPs’ data were collected electronically via the survey platform Qualtrics, and descriptive statistics were performed. Households with poultry reported vaccinating mostly against Newcastle disease (91.7%), fowl pox (48.1%) and Gumboro disease (37.0%), whilst households with small ruminants reported contagious caprine pleuropneumonia (62.2%), sheep and goat pox (17.1%), foot-and-mouth disease (7.3%) and peste des petits ruminants (7.3%). The households’ decision to vaccinate was mostly influenced by knowledge of diseases (82.4%), disease history on the farm (69.4%) and vaccine price (63.4%). Most households (54.6%) experienced challenges when purchasing vaccines, including high vaccine cost (78.0%), long distance from vaccine source (61.0%) and vaccine unavailability (21.2%). The findings suggest that improving the knowledge of livestock owners regarding the priority diseases and the benefits of vaccination, establishing more vaccine suppliers, improving vaccine distribution and access and training AHPs and households on appropriate vaccine storage and handling are necessary to improve vaccine adoption and ensure vaccine quality and effectiveness.

Carvacrol is an essential oil derived from oregano that is used as a natural additive to improve the efficiency of livestock nutrition. Residues of natural additives such as carvacrol should be monitored in food of animal origin to ensure consumer safety. The aim of this study was to appraise the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach coupled with liquid chromatography and mass spectrometry as a means of carvacrol analysis in chicken tissue.

Highly pathogenic avian influenza (HPAI) outbreaks caused by the Gs/Gd lineage of H5Nx viruses occur in Poland with increased frequency. The article provides an update on the HPAI situation in the 2020/2021 season and studies the possible factors that caused the exceptionally fast spread of the virus.

Carvacrol is an essential oil extracted from oregano which can be used as a natural additive in poultry litter and could have a positive impact not only on production rates but also on the quality of poultry meat. The aim of this study was to evaluate the effect of the addition of carvacrol to litter on weight gain and the occurrence of residues in chicken tissues.

Cases of salmonellosis in humans have been associated with consumption of eggs contaminated with this bacterial pathogen due to insufficient heat treatment. The most prevalent serotypes of Salmonella in Brazil include serotypes Enteritidis, Typhimurium, and Heidelberg. The first two serotypes are major causes for eggs to be withheld from sale and for recalls over Salmonella contamination concerns in both domestic and foreign markets. Eggs may be contaminated through transovarian infection (transovarial transmission) due to the presence of the microorganism in the hen’s oviduct and bacterial penetration of the eggshell. There is little data in the literature on the susceptibility of egg contamination and eggshell penetration by Brazilian serotypes of Salmonella. The present study aimed to evaluate the ability of S. Heidelberg and S. Typhimurium serotypes to penetrate through the eggshell and detect these bacteria in the albumen and yolk according to the thickness of the eggshell. SPF (specific-pathogen-free) eggs were artificially contaminated by contact with moist cotton containing Salmonella (15 x 108 CFU/ml). Eggs were divided into the following groups: negative control (not contaminated), S. Heidelberg, and S. Typhimurium. Subsequently, these eggs were incubated at 37°C, and their contents analyzed after 4 h and 24 h of incubation. The evaluation (assessment) of the contamination was performed by traditional bacteriology and confirmed by biochemical and serological tests. Treatments were compared with Fisher’s test using a SAS statistical software. For S. Heidelberg, the percentage of positivity (positive cases) was lower in both albumen and yolk at 4 h and 24 h intervals (33.33% and 3.7%, and 3.7% and 3.7%, respectively) compared to S. Typhimurium (26.63% and 7.41%, and 33.33% and 33.33%, respectively). These findings suggest that the former strain (S. Heidelberg) was unable to survive in the hostile environment of the albumen. In contrast, eggshell thickness had no significant correlation with the number of positive samples. In conclusion, the results obtained in the egg infection model show that the Salmonella strains tested were able to penetrate the eggshell and multiply in both the albumen and yolk and that S. Typhimurium proved to be the most efficient to grow within these portions of the egg.

This study describes the isolation, serotyping and genotyping of 54 infectious bronchitis virus (IBV) cases predominantly in KwaZulu-Natal and compared to several isolates from other South African provinces between 2011 and 2012 and several historic isolates. The results indicate the division of isolates into two different genotypes of IBV within the province, Massachusetts (Mass)-like and QX-like. The IBV Mass-like genotype was the most prevalent and was detected in 79% of the full spike protein S1 gene sequences. Variation up to 22.3% was detected within local Mass-type strains, supporting the hypothesis that multiple IBV serotypes may co-circulate in the same region simultaneously. Additionally, more conservation was observed amongst Mass serotypes versus QX-like serotypes, implying that vaccine use can influence the variability within the IBV population; this is deduced from the fact that the only live vaccine registered for use in South Africa at the time of the study was of Mass origin and no QX-like vaccines were available for use. This study offers the first published consolidation of IBV isolates from an area of South Africa and identifies variation within the IBV population of the broiler flock within the study area over a 2-year period.

The main goal of this study was to evaluate the protective efficacy of living attenuated Salmonella Typhimurium (S. Typhimurium) vaccine in poultry and to evaluate its use in control of salmonella infection in chickens. Oral vaccination of chickens within 36 hours after hatching and after 6 weeks from the first dose induced a strong humoral immune response as measured by ELISA. Challenge test was done with virulent strain of S. Typhimurium. Shedding of S. Typhimurium was detected during the first day, but after 14 days, salmonella could not be detected in the internal organs of vaccinated chickens compared with the non-vaccinated challenged chickens.

In a trial for comparison between the efficiency of single fowl pox (FP) vaccination and the efficiency of each combined FP and Avian encephalomyelitis (AE) vaccination and simultaneous vaccination with FP and Reo and with FP and Chicken anemia virus (CAV) vaccines our conclusion was that there is no antagonistic reaction between FP virus strain and each AE, Reo and CA viruses strains. In addition, humoral immune response against AE virus strain in case of combined AE+FP vaccination is markedly potent than that in case of single AE vaccination, more over the value of average EID50 of AE virus strain in several batches of combined AE+FP vaccines is significantly higher at P > 0.05 than that in several batches of single AE vaccines. On the other hand, immune response against FP virus strain and Reo virus strain in case of simultaneous vaccination with FP and Reo vaccines is higher than that in case of single FP vaccination and single Reo vaccination. Consequently, it is advisable to use combined live attenuated AE+FP vaccine instead of vaccination with single FP and AE separately. Also, application of simultaneous vaccination with FP and Reo vaccines is advisable as it is proved to be more beneficial than vaccination with each vaccine separately specially in case of that FP vaccine of low potency.

Merthiolate (Thiomersal) is known to be used as antimicrobial agent in inactivated vaccines without affecting vaccine potency. The present work investigated the effect of thiomersal contents in ND, AI and IBD inactivated vaccines on liver and kidney functions of vaccinated birds. The histopathological effect and the withdrawal time of such mercurial product from vaccinated chicken muscles were also investigated. Results revealed that residual thiomersal contents in ND, AI and IBD were 0.03; 0.02 and 0.03mg/ml respectively. Liver and kidney function parameters showed significant increases in serum activities of alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) up to the 4th week post vaccination. Serum urea was significantly decreased on the 3rd week in vaccinated birds compared to control ones. Significant increase in serum creatinine in vaccinated chickens was recorded on the 5th week post vaccination. Liver and kidney functions’ parameters remain high allover the experimental period (8 weeks). The histopathological examination of liver specimens revealed degeneration of hepatic cells and congestion of the central vein with inflammatory cell infiltration and congestion of blood vessels as well as coagulative necrosis. The spleen of vaccinated chickens showed depletion of lymphocytes while lungs showed thickening of the alveolar. Mercury contents in muscle were 0.72, 0.52; 0.046 and 0.00 mg/kg on the 1st, 2nd, 3rd and 4th week post last vaccination that considered safe to the consumer. It is recommended that vaccinated poultry with inactivated vaccines containing thiomersal should not be slaughtered before at least 4 weeks and it is preferable to use combined inactivated vaccines to reduce the thiomersal contents as possible.

A total of 620 egg samples from different species (chickens, ducks and ostriches) and 1615 poultry samples (chickens, ducks, pigeons, quails, turkeys and ostriches) were examined for salmonella infection. 12 salmonella isolates were obtained from the egg samples (1.9%) and 67 isolates from poultry samples (4.1%). Salmonella isolates were serotyped into S. enteritidis (25 isolates), S. typhimurium (17 isolates), S. infantis (12 isolates), S. montivideo (7 isolates), 3 isolates for each of S. rubislaw and S. cerro , 2 isolates for each of S. virginia, S. agona, S. poona, and S. derby and 1 isolate for each of S. sandiago and S. kentucky. The incidence of isolation from different poultry species was discussed in details. Antibiogram of the isolated salmonellae against 10 different antibiotics revealed that norofloxacin, ciprofloxacin, cepheridin and gentamycin gave the highest activity against different salmonella isolates while amoxicillin, tetracycline, and nitrofurantoin showed the highest resistance rate. Pathogenicity of the isolated serovars was tested in chickens. All isolates were found pathogenic with various degree of virulence. SDSPAGE protein analysis for the salmonella isolated form different poultry species revealed 12 protein bands ranged from 22-289 kDa. The differences were insufficient for reliable differentiation between the isolates and accordingly, it could be used beside other molecular techniques in differentiation between the salmonella strains.