Bacteria Isolations from Broiler and Layer Chicks in Zambia

Chick mortality (CM) is one of the major constraints to the expansion of the poultry industry in Zambia. Of the 2,829 avian disease cases submitted to the national diagnostic laboratory based at the Central Veterinary Research Institute in Lusaka between 1995 and 2007, 34.39% (973/2,829) were from CM cases. The disease accounted for 40.2% (218,787/544,903) mortality in the affected flocks with 89.6% (196,112/218,787) of the affected birds dying within seven days. Major bacteria species involved were Escherichia coli, Salmonella gallinarum, and Proteus species being isolated from 84.58%, 46.15%, and 26.93% of the reported CM cases (n = 973), respectively. Detection of Salmonella typhimurium, Salmonella enteritidis, and Salmonella dublin indicates that poultry has the potential of transmitting zoonotic pathogenic bacteria to humans. The proportion of Salmonella gallinarum reactors in the adult breeding stock was generally low (<0.5%) throughout the study period although its prevalence in CM cases was correlated (r = 0.68, P < 0.011) with seroprevalence of the same pathogen in the adult breeding stock. Given that the disease accounts for a large proportion of the avian diseases in Zambia as shown in the present study (34.39%, n = 2,829), it is imperative that an effective disease control strategy aimed at reducing its occurrence should be developed

The immunogenicity of a foot-and-mouth disease virus serotype O vaccine in commercial and subsistence cattle herds in Zambia

DATA AVAILABILITY STATEMENT : All datasets produced and analysed for this study are available from the corresponding author upon reasonable request.SUPPLEMENTARY MATERIALS : TABLE S1: The solid-phase competitive ELISA (SPCE) % inhibition results at 1:10 dilution (results for 1:30 dilution not shown) and the log reciprocal of virus neutralisation test (VNT) titres in subsistence (Rufunsa) and commercial (Chisamba) cattle herds vaccinated with either one (day 0) or two doses (day 0 and 28) of an FMDV serotype O vaccine.The recent introduction of foot-and-mouth disease (FMD) virus serotype O (O/EA-2 topotype) in Southern Africa has changed the epidemiology of the disease and vaccine requirements of the region. Commercial and subsistence cattle herds in Zambia were vaccinated with an FMD virus serotype O Manisa vaccine according to a double- or single-dose vaccination schedule. Heterologous antibody responses induced by this vaccine against a representative O/EA-2 virus from Zambia were determined. Virus neutralisation tests (VNTs) showed double-dosed cattle had a mean reciprocal log virus neutralisation titre of 2.02 (standard error [SE] = 0.16, n = 9) for commercial herds and 1.65 (SE = 0.17, n = 5) for subsistence herds 56 days after the first vaccination (dpv). Significantly lower mean titres were observed for single-dosed commercial herds (0.90, SE = 0.08, n = 9) and subsistence herds (1.15, SE = 0.18, n = 3) 56 dpv. A comparison of these results and those generated by solid-phase competitive ELISA (SPCE) tests showed a statistically significant positive correlation by Cohen’s kappa coefficient. Therefore, SPCE might be used in assessing the immunogenicity of vaccines in place of VNT. Furthermore, for this vaccine and field strain, a vaccination regime employing a two-dose primary course and revaccination after 4–6 months is likely to be appropriate.The Government of Zambia through the Ministry of Fisheries and Livestock, Department of Veterinary; the Department for Environment, Food, and Rural Affairs (Defra; UK), funded by the European Union; and The Pirbright Institute receives grant-aided support from the Biotechnology and Biological Sciences Research Council of the United Kingdom.https://www.mdpi.com/journal/vaccinesam2024Veterinary Tropical DiseasesSDG-02:Zero HungerSDG-03:Good heatlh and well-bein

Geographic distribution of cattle anthrax in Western Zambia

Cattle anthrax outbreaks have been reported in Western Province, Zambia since the 1970s. Although several efforts have been made to control these outbreaks, their persistent occurrence remains a major problem. To understand the current epidemiological situation, we analyzed the annual, seasonal, and geographical distributions of cattle anthrax in Zambia from 2000 to 2016. Results indicate a decrease in the annual number of reported cases and a change in geographical distribution of outbreaks. Anthrax vaccinations can influence the epidemiological situation of the Western Province; therefore, the seroprevalence of Bacillus anthracis protective antigen antibodies was determined in 1619 cattle. The overall seropositive rate was 24.9% (403/1619) and it varied among sampling areas, suggesting that anthrax vaccination programs must be reinforced in Zambia

Lung lesion score system in cattle: proposal for contagious bovine pleuropneumonia

Contagious bovine pleuropneumonia (CBPP) is a severe infectious disease caused by Mycoplasma mycoides subsp. mycoides. The peculiar pathological features of CBPP make desirable the assessment of ad hoc score methods to grade the disease in the affected animals. Thus, the present work aims to assess a new lung score system for CBPP. Our results indicate that the present score system strongly correlates with that previously published by Turner and could be effectively used in CBPP-affected animals

Use of Canonical Single Nucleotide Polymorphism (CanSNPs) to characterize Bacillus anthracis outbreak strains in Zambia between 1990 and 2014

Anthrax caused by Bacillus anthracis is an old and neglected zoonosis that continues to raise concerns in Southern Africa. In this study, twenty (20) slides with suspected isolates of B. anthracis from anthrax cases between 1990 and 2014 and two (2) from that of a vaccine strain were analysed using MLVA with 15 VNTRs and CanSNPs test. The results from the CanSNPs indicate that all anthrax outbreaks in Zambia between 1990 and 2014 were caused by the lineage A.Br.005/006 of the clade A. This indicates a common ancestral origin of the B. anthracis circulating in the country. This data has described several environmental, wildlife, livestock and human cases that occurred in a 24 year period, from the major areas where anthrax is endemic. The molecular characterization of isolates from anthrax outbreaks in Zambia has revealed a genetic structure in agreement with previous studies from neighbouring countries. Further studies are needed to elucidate how to better manage anthrax outbreaks and define the risk maps of Zambia

Development and application of a Bacillus anthracis protective antigen domain-1 in-house ELISA for the detection of anti-protective antigen antibodies in cattle in Zambia.

In Zambia, anthrax outbreaks among cattle are reported on nearly an annual basis. Presently, there is a lack of serological assays and information to develop an anthrax management and control strategy. In this study, an indirect enzyme-linked immunosorbent assay (ELISA) based on recombinant protective antigen domain 1 (rPA-D1) of Bacillus anthracis was developed and used to detect anti-PA antibodies in cattle in Zambia. An antigen coating of 10 ng/well and a serum dilution of 1:100 were determined to be the optimal rPA-D1 ELISA titration conditions. The intra- and inter-assay % coefficients of variation were less than 10% and 15%, respectively. The rPA-D1 ELISA could detect seroconversion in the cattle 1 month after anthrax vaccination. In a cross-sectional study conducted in the Western Province, Zambia, 187 serum samples from 8 herds of cattle were screened for anti-PA antibodies using the rPA-D1 ELISA. The seropositive rate of the serum samples was 8%, and the mean anti-PA antibody was 0.358 ELISA units. Additionally, we screened 131 cattle serum samples from Lusaka, which is a nonendemic area, and found no significant association between the antibody levels and sampling area (endemic versus nonendemic area). Conversely, significant differences were observed between the anti-PA antibody levels and herds, anti-PA antibody levels and vaccination status and anti-PA antibody levels and vaccination timing. Collectively, these findings suggest that the rPA-D1 ELISA is a useful tool for the detection of anti-PA antibodies in cattle in Zambia. The low proportion of seropositive sera indicates that there is inadequate cattle vaccination in the Western Province and, in addition to other epidemiological factors, this may precipitate the anthrax outbreak recurrence

Correction: Development and application of a Bacillus anthracis protective antigen domain-1 in-house ELISA for the detection of anti-protective antigen antibodies in cattle in Zambia.

[This corrects the article DOI: 10.1371/journal.pone.0205986.]