The aims of this study were twofold: to assess the welfare of two hybrids of laying hens in conventional cages and to investigate the effects of tier’s level on the integument condition and fearfulness. Two commercial hybrids, white Lohmann Selected Leghorn (LSL) and brown Lohmann Traditional (LT) at about 18 weeks of age were used in the current study and were housed at three hens / cage. No birds were beak-trimmed. External appearance of the body (scoring of plumage condition and skin injuries at body parts and comb), heterophil-lymphocyte (H-L) ratios and duration of tonic immobility (TI) were used as indicators of well-being. LSL birds showed better plumage condition and low H-L ratios than LT birds while no significant difference was recorded in TI test between the two hybrids. Hens housed in the top tier showed worse feather condition and more wounds than birds in middle and bottom tiers whereas for fear levels, no significant difference was revealed for hens from different tiers of cages. These results suggest that the welfare of LSL birds was relatively good compared to LT. Therefore, conventional cages can be used by the hens to a large extent if birds are properly selected to be specifically adapted to cages.

This study was carried out to investigate the prevalence, molecular characterization and pathogenicity of field infectious bursal disease virus (IBDV) isolates. Nine isolates of IBDV were isolated from 13 naturally infected broiler flocks. Detection of IBDV antigen was carried out by agar gel precipitation test (AGPT), followed by virus isolation in specific pathogen free (SPF) embryonated chicken eggs (ECE) and finally molecularly characterized and identified using reverse transcriptase polymerase chain reaction (RT-PCR). The obtained nine strains of IBDV by RT-PCR were further classified by using restriction fragment length polymorphism (RFLP) technique into (4) classical, (3) variant and (2) very virulent (vv) IBDV serotype (I). The pathogenicity of the isolated IBDV strains was detected by three passages in SPF ECEs and by experimental infection of one hundred 14 days old maternally immune layer chicks. The results showed that the mortality rate of the embryos was increased by increase the number of passages till the third passage where it reached 100% for all IBDV strains and the embryos showed typical lesions of IBDV. Chicks inoculated with variant IBDV strains showed morbidity rates of 60-80 %, without mortalities. Sacrificed birds showed atrophied bursae and thymus glands and enlarged thickened proventriculus. Groups infected with classical IBDV strains showed morbidity rates 40- 60,% with mortality 0-20%. The detectable lesions were muscular hemorrhages with variable bursal lesions. Inoculated chicks with vvIBDV strains showed 50-70% morbidity and mortality of rate was 30% with lesions of muscular hemorrhages, severe nephrosis with ureates in the ureters, hemorrhagic bursitis and pin point hemorrhages on the proventricular glands. Control negative non-infected group showed neither clinical signs nor mortalities along the observation period. The histopathological effect (lesion score) of IBDV strains on the bursa, spleen and thymus glands confirmed the previously mentioned results and revealed that the highest severity (score) for these organs were induced by vv IBDV strains.

African swine fever (ASF) is a contagious haemorrhagic disease associated with causing heavy economic losses to the swine industry in many African countries. In 2017, Zambia experienced ASF outbreaks in Mbala District (Northern province) and for the first time in Isoka and Chinsali districts (Muchinga province). Meanwhile, another outbreak was observed in Chipata District (Eastern province). Genetic analysis of part of the B646L gene, E183L gene, CP204L gene and the central variable region of the B602L gene of ASF virus (ASFV) associated with the outbreaks in Mbala and Chipata districts was conducted. The results revealed that the ASFV detected in Mbala District was highly similar to that of the Georgia 2007/1 isolate across all the genome regions analysed. In contrast, while showing close relationship with the Georgia 2007/1 virus in the B646L gene, the ASFV detected in Chipata District showed remarkable genetic variation in the rest of the genes analysed. These results suggest that the Georgia 2007/1-like virus could be more diverse than what was previously thought, underscoring the need of continued surveillance and monitoring of ASFVs within the south-eastern African region to better understand their epidemiology and the relationships between outbreaks and their possible origin.

Enterococcus species have developed from being commensal bacteria to leading pathogens that cause infections in humans and animals. The gastrointestinal tract of mammals is the normal habitat of these species. Virulence factors are proteins that are produced by the bacterium which are used to enhance their pathogenicity. The objectives of this study were to isolate Enterococcus spp. from livestock and companion animals, differentiate between the different sub-species and detect the presence of important virulence genes. Rectal and saliva swabs were collected from dogs and cats, whereas only rectal swabs were collected from cattle and cloacal swabs from chickens. Presumptive Enterococcus was selected using Bile Esculin Azide (BEA) agar, and Enterococcus species were confirmed using the polymerase chain reaction (PCR) by amplifying the tuf gene. In order to differentiate between E. faecalis and E. faecium, a multiplex PCR was used to detect the SodA gene. The genes responsible for gelatinase production (gelE) and for conjugation (ccf) were also detected using PCR. Out of 211 animal swabs, 182 (86%) were positive for the tuf gene. Overall, there were 55 isolates of E. faecalis (30%) compared to 22 isolates of E. faecium (12%). The virulence genes had a prevalence of 52% and 36% for gelE and ccf, respectively, in all animal hosts. The results demonstrated that chicken cloacal samples had the highest prevalence for E. faecalis, gelE and ccf genes compared to all the other isolates detected from other animal hosts. The results also demonstrated a statistically significant (p < 0.05) association between the prevalence of virulence genes (gelE and ccf) and animal species from which Enterococcus spp. was isolated. We provided evidence that healthy livestock and companion animals can harbour pathogenic Enterococcus that can be transferred via the food chain as well as through close association such as petting and licking of humans. This study partially demonstrated that Enterococci spp. are capable of evolving from being simple commensal bacteria to becoming pathogens that cause infection in humans and animals through the acquisition of virulence factors through mobile genetic elements.