Epidemiological Tools in Focus: A Comprehensive Assessment of Their Role in Addressing Infectious Disease Challenges in Zambia

In the relentless pursuit of mitigating infectious diseases, this investigative study critically examines the nuanced application and effectiveness of epidemiological tools within the context of Zambia. The study meticulously navigates the landscape of infectious diseases in Zambia, considering its unique ecological and socio-economic features. Employing a rigorous methodology that integrates primary data from epidemiological reports, field observations, and laboratory analyses with insights from diverse scientific literature, the study investigates the types and applications of epidemiological tools such as spatial analysis, case-control studies, molecular epidemiology, and serological assays. Unfolding the challenges posed by resource constraints, data reliability issues, and the dynamic nature of infectious diseases in Zambia, the study offers a comprehensive assessment that extends to the implications of these tools for informed public health decision-making. This scholarly inquiry concludes by affirming the significance of ongoing refinement and adaptation of epidemiological tools, emphasizing their pivotal role in addressing infectious disease challenges within Zambia and advocating for their continued enhancement on the global public health stage

Genetic characterisation of African swine fever virus from 2017 outbreaks in Zambia: Identification of p72 genotype II variants in domestic pigs

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

Multi-scale assessment of the livestock sector for policy design in Zambia

While livestock constitute a strategic sector to reduce poverty and enhance growth in developing countries, decision makers often lack data reflecting the diversity of livestock functions and systems. We therefore mobilised the Livestock Sector Investment Policy Toolkit to assess the economic contributions of livestock in Zambia. Valuing their plural contributions by system, we found that mixed rainfed systems were the main contributors to added value, even if specialised intensive systems provided around 45% of meat and milk production. Demand-oriented policies promoting intensive systems would not have the same effects on economic growth as growth-oriented policies focusing on smallholder mixed farming. (C) 2019 The Authors. Published by Elsevier Inc. on behalf of The Society for Policy Modeling

Prevalence of bovine fascioliasis and economic impact associated with liver condemnation in abattoirs in Mongu district of Zambia

Abstract Background Fascioliasis is a trematode zoonotic snail-borne disease of public health and economic importance. The disease causes liver damage and is hardly recognized by medical personnel hence, is rarely considered as the differential diagnosis. In animals, the disease leads to mortalities, growth retardation, drop in livestock production and condemnation of the infected livers during meat inspection. The cross-sectional study was conducted from 2013 to 2017 in abattoirs in Mongu district, Western province of Zambia. Each selected carcass was examined macroscopically for bovine fascioliasis by dissecting the liver and checking for adult liver flukes. Infested and condemned livers were weighed and incinerated. Results A total of 69,152 carcasses with their livers was examined at the abattoirs for adult Fasciola worms and 44,511 (64.4%) were positive. According to the intensity of pathological lesions, 55.3% constituted severely affected livers, 30.3% were moderately affected livers and 14.4% were lightly affected livers. Our observation revealed that the most prevalent liver fluke identified was Fasciola gigantica (56.1%) and it mostly affected the poor body conditioned animals (71.4%). The study also indicated that 164,600 kg liver was condemned and destroyed. This reduced the income base for small-scale livestock farmers to about ZMW 7,407,000.00, which was equivalent to 592,560 USD. Conclusion In conclusion, our study suggests that the prevalence of bovine fascioliasis was high resulting in a large amount of liver being condemned and destroyed, leading to economic losses for affected livestock farmers in the area. Consequently, there is a need to take the necessary measures to control the disease and create awareness among medical personnel to consider it as a differential diagnosis in all functional liver deficiencies due to the zoonotic nature of the disease

Sequence Diversity of Tp1 and Tp2 Antigens and Population Genetic Analysis of Theileria parva in Unvaccinated Cattle in Zambia’s Chongwe and Chisamba Districts

East Coast Fever (ECF), caused by Theileria parva, is a major constraint to improved livestock keeping in east and central Africa, including Zambia. To understand the dynamics and determine the candidates for immunization in Zambia’s Chongwe and Chisamba districts, a combination of Tp1 and Tp2 gene sequencing and microsatellite analysis using nine markers was conducted from which an abundance of Muguga, Kiambu, Serengeti and Katete epitopes in the field samples was obtained. Phylogenetic analysis showed six (Tp1) and three (Tp2) clusters with an absence of geographical origin clustering. The majority of haplotypes were related to Muguga, Kiambu, Serengeti and Katete, and only a few were related to Chitongo. Both antigens showed purifying selection with an absence of positive selection sites. Furthermore, low to moderate genetic differentiation was observed among and within the populations, and when vaccine stocks were compared with field samples, Chongwe samples showed more similarity to Katete and less to Chitongo, while Chisamba samples showed similarity to both Katete and Chitongo and not to Muguga, Kiambu or Serengeti. We conclude that the use of Katete stock for immunization trials in both Chongwe and Chisamba districts might produce desirable protection against ECF

Hepatitis E virus infection in pigs : a first report from Zambia

While evidence suggests presence of HEV infection in humans in Zambia, currently, there is no information on its occurrence in domestic pigs. Here, we investigated the presence of HEV antibodies and genome in domestic pigs in Zambia. Sera (n = 484) from domestic pigs were screened for antibodies against HEV by ELISA while genome detection in fecal (n = 25) and liver (n = 100) samples from slaughter pigs was conducted using nested RT-PCR assay. Overall, seroprevalence was 47.7% (231/484) while zoonotic genotype 3 HEV RNA was detected in 16.0% (20/125) of slaughtered pigs. This is the first report to highlight occurrence of HEV infection in domestic pigs in Zambia. This finding suggests possible contamination of the pork supply chain. Moreover, there is a potential risk of zoonotic transmission of HEV to abattoir workers, pig farmers and handlers

An unusually long Rift valley fever inter-epizootic period in Zambia : Evidence for enzootic virus circulation and risk for disease outbreak

Rift valley fever (RVF) is a mosquito-borne disease of animals and humans. Although RVF outbreaks are usually reported at 5-15-year intervals in sub-Saharan Africa, Zambia has experienced an unusually long inter-epizootic/-epidemic period of more than three decades. However, serological evidence of RVF virus (RVFV) infection in domestic ruminants during this period underscores the need for comprehensive investigation of the mechanisms of virus perpetuation and disease emergence. Mosquitoes (n = 16,778) captured from eight of the ten provinces of Zambia between April 2014 and May 2019 were pooled (n = 961) and screened for RVFV genome by a pan-phlebo RT-PCR assay. Aedes mosquito pools (n = 85) were further screened by nested RT-PCR assay. Sera from sheep (n = 13), goats (n = 259) and wild ungulates (n = 285) were screened for RVFV antibodies by ELISA while genome detection in pooled sera (n = 276) from domestic (n = 248) and wild ungulates (n = 37) was performed by real-time RT-PCR assay. To examine the association between the long inter-epizootic period and climatic variables, we examined El Nino-Southern Oscillation indices, precipitation anomalies, and normalized difference vegetation index. We then derived RVF risk maps by exploring climatic variables that would favor emergence of primary RVFV vectors. While no RVFV genome could be detected in pooled mosquito and serum samples, seroprevalence was significantly high (OR = 8.13, 95% CI [4.63-14.25]) in wild ungulates (33.7%; 96/285) compared to domestic ruminants (5.6%; 16/272). Retrospective analysis of RVF epizootics in Zambia showed a positive correlation between anomalous precipitation (La Nina) and disease emergence. On risk mapping, whilst northern and eastern parts of the country were at high risk, domestic ruminant population density was low (21 animals/km(2)). Besides evidence of silent circulation of RVFV and the risk of disease emergence in some areas, wildlife may play a role in the maintenance of RVFV in Zambia

Rickettsia lusitaniae in Ornithodoros Porcinus Ticks, Zambia

Rickettsial pathogens are amongst the emerging and re-emerging vector-borne zoonoses of public health importance. Though traditionally considered to be transmitted by ixodid ticks, the role of argasid ticks as vectors of these pathogens is increasingly being recognized. While bat-feeding (Ornithodoros faini) and chicken-feeding (Argas walkerae) argasid ticks have been shown to harbor Rickettsia pathogens in Zambia, there are currently no reports of Rickettsia infection in southern Africa from warthog-feeding (Phacochoerus africanus) soft ticks, particularly Ornithodoros moubata and Ornithodoros porcinus. Our study sought to expand on the existing knowledge on the role of soft ticks in the epidemiology of Rickettsia species through screening for Rickettsia pathogens in warthog burrow-dwelling soft ticks from two national parks in Zambia. The tick species from which Rickettsia were detected in this study were identified as Ornithodoros porcinus, and an overall minimal Rickettsia infection rate of 19.8% (32/162) was observed. All of the sequenced Rickettsia were identified as Rickettsia lusitaniae based on nucleotide sequence similarity and phylogenetic analysis of the citrate synthase (gltA) and 17kDa common antigen (htrA) genes. Utilizing all of the gltA (n = 10) and htrA (n = 12) nucleotide sequences obtained in this study, BLAST analysis showed 100% nucleotide similarity to Rickettsia lusitaniae. Phylogenetic analysis revealed that all of the Zambian gltA and htrA gene sequences could be grouped with those of Rickettsia lusitaniae obtained in various parts of the world. Our data suggest that Rickettsia lusitaniae has a wider geographic and vector range, enhancing to our understanding of Rickettsia lusitaniae epidemiology in sub-Saharan Africa