Bernard M. Hang’ombe

Novel Arenavirus, Zambia

To investigate arenavirus in Zambia, we characterized virus from the kidneys of 5 arenavirus RNA–positive rodents (Mastomys natalensis) among 263 captured. Full-genome sequences of the viruses suggested that they were new strains similar to Lassa virus–related arenaviruses. Analyzing samples from additional rodents and other species can elucidate epizootiologic aspects of arenaviruses.

Molecular identification of non-tuberculous mycobacteria isolated from clinical specimens in Zambia.

BackgroundThe emergence of Acquired Immunodeficiency Syndrome has highlighted the increased incidence and importance of the disease caused by Non-tuberculous Mycobacteria (NTM). While disease due to M. avium-intracellulare complex is apparently common throughout the world, other Non-tuberculous mycobacterial species have been isolated from both immunocompromised and immunocompetent individuals. The increasing number of infections caused by these organisms has made it clinically important to quickly identify mycobacterial species. The diagnosis of a pathogenic versus a non-pathogenic species not only has epidemiological implications but is also relevant to the demands of patient management. Since antibiotic treatment varies according to the species encountered, species identification would reduce the burden of some of these emerging opportunistic pathogens especially in immunocompromised patients and improve their quality of life.FindingsA total of 91 NTM suspected isolates from four regions of Zambia were included in the study. These isolates were identified using the sequence analysis of the 16S-23S rRNA intergenic transcribed spacer (ITS) region of Mycobacteria.Fifty-four of the 91 (59%) isolates were identified as NTM and these included M. intracellulare (27.8%), M. lentiflavum (16.7%), M. avium (14.8%), M. fortuitum (7.4%), M. gordonae (7.4%), M. kumamotonense (3.7%), M. indicus pranii (3.7%), M. peregrinum (3.7%), M. elephantis (1.85%), M. flavescens (1.85%), M. asiaticum (1.85%), M. bouchedurhonense (1.85%), M. chimaera (1.85%), M. europaeum (1.85%), M. neourum (1.85%), M. nonchromogenicum (1.5%).ConclusionThe study has shown that DNA sequencing of the ITS region may be useful in the preliminary identification of NTM species. All species identified in this study were potentially pathogenic.

Comparison of complement fixation test, competitive ELISA and LppQ ELISA with post-mortem findings in the diagnosis of contagious bovine pleuropneumonia (CBPP)

The complement fixation test (CFT), the c-ELISA and an indirect LppQ ELISA were compared to post-mortem (PM) inspection for the diagnosis of contagious bovine pleuropneumonia (CBPP). Sera from 797 cattle in the CBPP affected area of Kazungula, Zambia and 202 sera from Lusaka, Zambia, a CBPP-free area were used. The clinical history of CBPP was recorded and all the cattle from Kazungula were slaughtered and PM inspections conducted. The prevalence of CBPP in Kazungula was 67.5% (95%CI 67.2%, 70.8%), 52.6% (95%CI 49.2%, 56.2%), 59.0% (95%CI 55.5%, 62.4%) and 44.4% (95%CI 41.0%, 47.9%) using PM inspection, CFT, c-ELISA and LppQ ELISA, respectively. Three of the 202 negative control animals tested positive on the c-ELISA although they were from a known CBPP negative zone. In this study, the c-ELISA was more sensitive in detecting cattle with lesions in the chronic stage than any other test whilst the CFT detected more during the onset stage. No single serological test could detect all stages of CBPP infection, therefore the use of more than one test is advised.

Challenges of controlling contagious bovine pleuropneumonia in sub-Saharan Africa

Contagious bovine pleuropneumonia (CBPP) is a disease of economic importance that is widely distributed in sub-Saharan African and contributes significantly to cattle morbidity and mortality. Control of CBPP offers a number of challenges as a result many developing countries in Africa are still struggling with this disease. In this study, we look at the challenges encountered in CBPP control in sub-Saharan Africa from the Zambian perspective. In conducting this study, we reviewed scientific literature and reports from the Ministry of Agriculture and Livestock and related animal institutions, and also made interviews with experts and key government officials involved in CBPP control in Zambia. Among the challenges identified for the successful control of CBPP were as follows: failure in the delivery of veterinary services, lack of a cattle identification system, natural phenomenon, livestock husbandry systems in the traditional sector, human movements, traditional practices among cattle farmers and cattle marketing systems. It was seen that the epidemiology of CBPP in Zambia is influenced by both ecological and anthological factors. Therefore, design and implementation of any control or eradication programme should be area/regional-dependent taking into account the different factors influencing disease transmission and maintenance.

Molecular epidemiology of pathogenic Leptospira spp. in the straw-colored fruit bat (Eidolon helvum) migrating to Zambia from the Democratic Republic of Congo

Abstract The role played by bats as a potential source of transmission of Leptospira spp. to humans is poorly understood, despite various pathogenic Leptospira spp. being identified in these mammals. Here, we investigated the prevalence and diversity of pathogenic Leptospira spp. that infect the straw-colored fruit bat (Eidolon helvum). We captured this bat species, which is widely distributed in Africa, in Zambia during 2008–2013. We detected the flagellin B gene (flaB) from pathogenic Leptospira spp. in kidney samples from 79 of 529 E. helvum (14.9%) bats. Phylogenetic analysis of 70 flaB fragments amplified from E. helvum samples and previously reported sequences, revealed that 12 of the fragments grouped with Leptospira borgpetersenii and Leptospira kirschneri; however, the remaining 58 flaB fragments appeared not to be associated with any reported species. Additionally, the 16S ribosomal RNA gene (rrs) amplified from 27 randomly chosen flaB-positive samples was compared with previously reported sequences, including bat-derived Leptospira spp. All 27 rrs fragments clustered into a pathogenic group. Eight fragments were located in unique branches, the other 19 fragments were closely related to Leptospira spp. detected in bats. These results show that rrs sequences in bats are genetically related to each other without regional variation, suggesting that Leptospira are evolutionarily well-adapted to bats and have uniquely evolved in the bat population. Our study indicates that pathogenic Leptospira spp. in E. helvum in Zambia have unique genotypes.

Development of a One Health National Capacity in Africa

Among the many challenges to health, infectious diseases stand out for their ability to have a profound impact on humans and animals. The recent years have witnessed an increasing number of novel infectious diseases. The numerous examples of infections which originated from animals suggest that the zoonotic pool is an important and potentially rich source of emerging diseases. Since emergence and re-emergence of pathogens, and particularly zoonotic agents, occur at unpredictable rates in animal and human populations, infectious diseases will constitute a significant challenge for the public health and animal health communities in the twenty-first century. The African continent suffers from one of the highest burdens of infectious diseases of humans and animals in the world but has the least capacity for their detection, identification and monitoring. Lessons learnt from recent zoonotic epidemics in Africa and elsewhere clearly indicate the need for coordinated research, interdisciplinary centres, response systems and infrastructures, integrated surveillance systems and workforce development strategies. More and stronger partnerships across national and international sectors (human health, animal health, environment) and disciplines (natural and social sciences) involving public, academic and private organisations and institutions will be required to meet the present and future challenges of infectious diseases. In order to strengthen the efficiency of early warning systems, monitoring trends and disease prediction and timely outbreak interventions for the benefit of the national and international community, it is essential that each nation improves its own capacity in disease recognition and laboratory competence. The SACIDS, a One Health African initiative linking southern African academic and research institutions in smart partnership with centres of science excellence in industrialised countries as well as international research centres, strives to strengthen Africas capacity to detect, identify and monitor infectious diseases of humans and animals, to better manage health and socio-economic risks posed by them, and to improve research capacity in investigating the biologic, socio-economic, ecologic and anthropogenic factors responsible for emergence and re-emergence of infectious diseases.

Molecular characterization of infectious bursal disease viruses detected in vaccinated commercial broiler flocks in Lusaka, Zambia

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive viral disease of young chickens and remains one of the economically most important diseases threatening the poultry industry worldwide. In this study, 16 and 11 nucleotide sequences of the VP2 hypervariable region (VP2-HVR) and part of VP1, respectively, of IBD virus (IBDV) detected in vaccinated broiler chickens in Lusaka in 2012 were determined. Phylogenetic analysis revealed that these Zambian IBDVs separated into three genotypes of very virulent (VV) IBDVs. Although the majority of these viruses belonged to the African VV type (VV1), which consisted of viruses from West Africa, South Africa and Zambia, one virus belonged to the East African VV type (VV2). Interestingly, a Zambian IBDV belonging to the VV3 genotype (composed of viruses from several continents) clustered with attenuated vaccine strains. Although sequence analysis of VP2-HVR showed that all detected Zambian IBDVs had conserved putative virulence marker amino acids (i.e., 222A, 242I, 256I, 294I and 299S), one virus had two unique amino acid substitutions, N280S and E300A. This study demonstrates the diversity of Zambian IBDVs and documents for the first time the possible involvement of attenuated vaccine strains in the epidemiology of IBD in Zambia. Strict biosecurity of poultry farms, monitoring of live vaccine use in the field, surveillance and characterization of IBDV in poultry and development of a vaccine from local or regional IBDV field strains are recommended for improved IBD control in Zambia.

Distinct Lineages of Bufavirus in Wild Shrews and Nonhuman Primates

Viral metagenomic analysis identified a new parvovirus genome in the intestinal contents of wild shrews in Zambia. Related viruses were detected in spleen tissues from wild shrews and nonhuman primates. Phylogenetic analyses showed that these viruses are related to human bufaviruses, highlighting the presence and genetic diversity of bufaviruses in wildlife.

Pathological and molecular diagnosis of the 2013 African swine fever outbreak in Lusaka, Zambia

African swine fever (ASF) is a highly contagious and fatal hemorrhagic viral disease of domestic pigs. The disease is widespread in sub-Saharan Africa and has repeatedly been introduced into other continents. The current study describes the diagnostic investigations of a hemorrhagic disease that was reported in pigs in Lusaka (October 2013), Zambia. Necropsy, histopathology, and molecular diagnosis using polymerase chain reaction and sequence analysis confirmed the disease to be ASF. The sequences obtained showed high similarity to previously isolated ASF viruses. Consistent surveillance and rapid diagnosis of the disease is recommended to prevent future outbreaks and economic losses as there is currently no vaccine against the disease.

Molecular, serological and epidemiological observations after a suspected outbreak of plague in Nyimba, eastern Zambia

Plague is a re-emerging zoonotic disease caused by the bacterium Yersinia pestis. The disease has caused periodic global devastation since the first outbreak in the 6th century. Two months after a suspected plague outbreak in Nyimba district, samples were collected from 94 livestock (goats and pigs), 25 rodents, 6 shrews and 33 fleas. Enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) techniques were used to investigate the presence of Y. pestis, which showed that 16.0% (4/25) of rodents, 16.7% (1/6) of shrews (Crocidura spp) and 6.0% (5/83) of goats were positive for IgG antibodies against Fraction 1 antigen of Y. pestis. Plasminogen activator (Pla) gene (DNA) of Y. pestis was detected in five pools containing 36.4% (12/33) fleas collected from pigs (n = 4), goats (n = 5) and rodents (n = 3). The detection of Pla gene in fleas and IgG antibodies against Fraction1 antigen in rodents, shrews and goats suggest that Y. pestis had been present in the study area in the recent past.