Infectious diseases are serious constraints for improving livestock productivity. Bovine viral diarrhoea virus (BVDV) is a virus causing grave economic losses throughout the cattle producing world. Infection is often not apparent, but the virus can also cause respiratory signs, diarrhoea, reproductive problems and immunosuppression. Risk factors for disease transmission include, but are not limited to, herd size, animal trade and grazing on communal pastures. Several prevalence studies have been conducted in southern Africa, but in Botswana the occurrence is largely unknown. In this study, blood samples were obtained from 100 goats from three villages around the capital city, Gaborone. Also, 364 blood samples from cattle around Gaborone, collected as part of another study, were analysed. The detected antibody prevalence was 0% in goats and 53.6% in cattle when using a competitive enzyme-linked immunoassay. Three animals from two different herds were positive for viral nucleic acids on polymerase chain reaction. The two herds with viraemic animals had significantly higher antibody prevalence compared to the other herds. Also, two of the detected viruses were sequenced and found to be most similar to BVDV-1a. To the authors' knowledge, this is the first time that sequencing has been performed on BVDV isolated in Botswana.

Infectious diseases are serious constraints for improving livestock productivity. Bovine viral diarrhoea virus (BVDV) is a virus causing grave economic losses throughout the cattle producing world. Infection is often not apparent, but the virus can also cause respiratory signs, diarrhoea, reproductive problems and immunosuppression. Risk factors for disease transmission include, but are not limited to, herd size, animal trade and grazing on communal pastures. Several prevalence studies have been conducted in southern Africa, but in Botswana the occurrence is largely unknown. In this study, blood samples were obtained from 100 goats from three villages around the capital city, Gaborone. Also, 364 blood samples from cattle around Gaborone, collected as part of another study, were analysed. The detected antibody prevalence was 0% in goats and 53.6% in cattle when using a competitive enzyme-linked immunoassay. Three animals from two different herds were positive for viral nucleic acids on polymerase chain reaction. The two herds with viraemic animals had significantly higher antibody prevalence compared to the other herds. Also, two of the detected viruses were sequenced and found to be most similar to BVDV-1a. To the authors’ knowledge, this is the first time that sequencing has been performed on BVDV isolated in Botswana.

The effective control of tsetse flies (Diptera; Glossinidae), the biological vectors of trypanosome parasites that cause human African trypanosomosis and African animal trypanosomosis throughout sub-Saharan Africa, is crucial for the development of productive livestock systems. The degree of genetic isolation of the targeted populations, which indicate reinvasion potential from uncontrolled areas, will be critical to establish a control strategy. Molecular and morphometrics markers were used to assess the degree of genetic isolation between seemingly fragmented populations of Glossina brevipalpis Newstead and Glossina austeni Newstead present in South Africa. These populations were also compared with flies from adjacent areas in Mozambique and Eswatini. For the molecular markers, deoxyribonucleic acid was extracted, a r16S2 Polymerase chain reaction (PCR) was performed and the PCR product sequenced. Nine landmarks were used for the morphometrics study as defined by vein intersections in the right wings of female flies. Generalised Procrustes analyses and regression on centroid size were used to determine the Cartesian coordinates for comparison between populations. Both methods indicated an absence of significant barriers to gene flow between the G. brevipalpis and G. austeni populations of South Africa and southern Mozambique. Sustainable control can only be achieved if implemented following an area-wide management approach against the entire G. brevipalpis and G. austeni populations of South Africa and southern Mozambique. Limited gene flow detected between the G. austeni population from Eswatini and that of South Africa or Mozambique may imply that these two populations are in the proses of becoming isolated.

The effective control of tsetse flies (Diptera; Glossinidae), the biological vectors of trypanosome parasites that cause human African trypanosomosis and African animal trypanosomosis throughout sub-Saharan Africa, is crucial for the development of productive livestock systems. The degree of genetic isolation of the targeted populations, which indicate reinvasion potential from uncontrolled areas, will be critical to establish a control strategy. Molecular and morphometrics markers were used to assess the degree of genetic isolation between seemingly fragmented populations of Glossina brevipalpis Newstead and Glossina austeni Newstead present in South Africa. These populations were also compared with flies from adjacent areas in Mozambique and Eswatini. For the molecular markers, deoxyribonucleic acid was extracted, a r16S2 Polymerase chain reaction (PCR) was performed and the PCR product sequenced. Nine landmarks were used for the morphometrics study as defined by vein intersections in the right wings of female flies. Generalised Procrustes analyses and regression on centroid size were used to determine the Cartesian coordinates for comparison between populations. Both methods indicated an absence of significant barriers to gene flow between the G. brevipalpis and G. austeni populations of South Africa and southern Mozambique. Sustainable control can only be achieved if implemented following an area-wide management approach against the entire G. brevipalpis and G. austeni populations of South Africa and southern Mozambique. Limited gene flow detected between the G. austeni population from Eswatini and that of South Africa or Mozambique may imply that these two populations are in the proses of becoming isolated.

Eight ixodid tick species were collected from 173 African savanna elephants (Loxodonta africana) in Kenya, northern Mozambique and Zimbabwe, and two species were collected from six African forest elephants (Loxodonta cyclotis) in the Republic of Congo. A new host record is reported for Amblyomma eburneum. A list of ticks collected from elephants in various African countries, and stored in the United States National Tick Collection, is supplied as well as an annotated checklist of the 27 ixodid tick species that have been collected from African elephants. The geographic distributions and alternative hosts of the various tick species collected from elephants are briefly discussed.

Eight ixodid tick species were collected from 173 African savanna elephants (Loxodonta africana) in Kenya, northern Mozambique and Zimbabwe, and two species were collected from six African forest elephants (Loxodonta cyclotis) in the Republic of Congo. A new host record is reported for Amblyomma eburneum. A list of ticks collected from elephants in various African countries, and stored in the United States National Tick Collection, is supplied as well as an annotated checklist of the 27 ixodid tick species that have been collected from African elephants. The geographic distributions and alternative hosts of the various tick species collected from elephants are briefly discussed.

In Zimbabwe, there have been no chlamydiosis and limited brucellosis studies in goats. This study was conducted to determine the seroprevalence and risk factors of the two diseases in goats at three different livestock–wildlife interface areas: porous, non-porous and non-interface in the south-eastern lowveld of Zimbabwe. Collected sera (n = 563) were tested for Brucella antibodies using the Rose Bengal plate test (RBPT) and the complement fixation test (CFT); and for Chlamydia abortus antibodies using the CFT. All tested goats were negative for Brucella antibodies. Overall, chlamydial seroprevalence was 22%. The porous [c2 = 9.6, odds ratio (OR) = 2.6, p = 0.002] and non-porous (c2 = 37.5, OR = 5.8, p < 0.00001) interfaces were approximately three and six times more likely to be chlamydial seropositive than the non-interface area, respectively. Chlamydial seroprevalence was not associated with sex (c2 = 0.5, OR = 1.2, p = 0.5), abortion history in female goats (c2 = 0.7, OR = 1.3, p = 0.4), keeping goats with cattle (c2 = 0.2, OR = 1.5, p = 0.7) or flock size (c2 = 0.03, OR = 1.4, p = 0.9). Our study provides the first serological evidence of chlamydiosis in goats in Zimbabwe and the results suggest that proximity to wildlife is associated with increased chlamydial seropositivity. Further studies are required to determine the role of chlamydial infection on goat reproductive failure and that of wildlife on C. abortus transmission to domestic ruminants.

In Zimbabwe, there have been no chlamydiosis and limited brucellosis studies in goats. This study was conducted to determine the seroprevalence and risk factors of the two diseases in goats at three different livestock–wildlife interface areas: porous, non-porous and non-interface in the south-eastern lowveld of Zimbabwe. Collected sera (n = 563) were tested for Brucella antibodies using the Rose Bengal plate test (RBPT) and the complement fixation test (CFT); and for Chlamydia abortus antibodies using the CFT. All tested goats were negative for Brucella antibodies. Overall, chlamydial seroprevalence was 22%. The porous [c2 = 9.6, odds ratio (OR) = 2.6, p = 0.002] and non-porous (c2 = 37.5, OR = 5.8, p < 0.00001) interfaces were approximately three and six times more likely to be chlamydial seropositive than the non-interface area, respectively. Chlamydial seroprevalence was not associated with sex (c2 = 0.5, OR = 1.2, p = 0.5), abortion history in female goats (c2 = 0.7, OR = 1.3, p = 0.4), keeping goats with cattle (c2 = 0.2, OR = 1.5, p = 0.7) or flock size (c2 = 0.03, OR = 1.4, p = 0.9). Our study provides the first serological evidence of chlamydiosis in goats in Zimbabwe and the results suggest that proximity to wildlife is associated with increased chlamydial seropositivity. Further studies are required to determine the role of chlamydial infection on goat reproductive failure and that of wildlife on C. abortus transmission to domestic ruminants.

Peste des petits ruminant (PPR) is a highly contagious, infectious viral disease of small ruminant species which is caused by the peste des petits ruminants virus (PPRV), the prototype member of the Morbillivirus genus in the Paramyxoviridae family. Peste des petits ruminant was first described in West Africa, where it has probably been endemic in sheep and goats since the emergence of the rinderpest pandemic and was always misdiagnosed with rinderpest in sheep and goats. Since its discovery PPR has had a major impact on sheep and goat breeders in Africa and has therefore been a key focus of research at the veterinary research institutes and university faculties of veterinary medicine in Africa. Several key discoveries were made at these institutions, including the isolation and propagation of African PPR virus isolates, notable amongst which was the Nigerian PPRV 75/1 that was used in the scientific study to understand the taxonomy, molecular dynamics, lineage differentiation of PPRV and the development of vaccine seeds for immunisation against PPR. African sheep and goat breeds including camels and wild ruminants are frequently infected, manifesting clinical signs of the disease, whereas cattle and pigs are asymptomatic but can seroconvert for PPR. The immunisation of susceptible sheep and goats remains the most effective and practical control measure against PPR. To carry out PPR vaccination in tropical African countries with a very high temperature, a thermostable vaccine using the rinderpest lyophilisation method to the attenuated Nigeria 75/1 PPR vaccine strain has been developed, which will greatly facilitate the delivery of vaccination in the control, prevention and global eradication of PPR. Apart from vaccination, other important questions that will contribute towards the control and prevention of PPR need to be answered, for example, to identify the period when a susceptible naïve animal becomes infectious when in contact with an infected animal and when an infectious animal becomes contagious.

Peste des petits ruminant (PPR) is a highly contagious, infectious viral disease of small ruminant species which is caused by the peste des petits ruminants virus (PPRV), the prototype member of the Morbillivirus genus in the Paramyxoviridae family. Peste des petits ruminant was first described in West Africa, where it has probably been endemic in sheep and goats since the emergence of the rinderpest pandemic and was always misdiagnosed with rinderpest in sheep and goats. Since its discovery PPR has had a major impact on sheep and goat breeders in Africa and has therefore been a key focus of research at the veterinary research institutes and university faculties of veterinary medicine in Africa. Several key discoveries were made at these institutions, including the isolation and propagation of African PPR virus isolates, notable amongst which was the Nigerian PPRV 75/1 that was used in the scientific study to understand the taxonomy, molecular dynamics, lineage differentiation of PPRV and the development of vaccine seeds for immunisation against PPR. African sheep and goat breeds including camels and wild ruminants are frequently infected, manifesting clinical signs of the disease, whereas cattle and pigs are asymptomatic but can seroconvert for PPR. The immunisation of susceptible sheep and goats remains the most effective and practical control measure against PPR. To carry out PPR vaccination in tropical African countries with a very high temperature, a thermostable vaccine using the rinderpest lyophilisation method to the attenuated Nigeria 75/1 PPR vaccine strain has been developed, which will greatly facilitate the delivery of vaccination in the control, prevention and global eradication of PPR. Apart from vaccination, other important questions that will contribute towards the control and prevention of PPR need to be answered, for example, to identify the period when a susceptible naïve animal becomes infectious when in contact with an infected animal and when an infectious animal becomes contagious.

Between July and September 2017, samples collected from six unvaccinated chickens in Namibia were shown to be positive for infectious bursal disease virus (IBDV) by RT-PCR. Partial sequence and phylogenetic analysis of the VP1 and VP2 genes from six viruses revealed that they all belong to the very virulent pathotype (Genogroup 3) and are genetically very similar to IBDVs identified in neighbouring Zambia. This is the first molecular characterisation of IBDV in Namibia and has implications on the control and management of the disease in the country.

Between July and September 2017, samples collected from six unvaccinated chickens in Namibia were shown to be positive for infectious bursal disease virus (IBDV) by RT-PCR. Partial sequence and phylogenetic analysis of the VP1 and VP2 genes from six viruses revealed that they all belong to the very virulent pathotype (Genogroup 3) and are genetically very similar to IBDVs identified in neighbouring Zambia. This is the first molecular characterisation of IBDV in Namibia and has implications on the control and management of the disease in the country.

Lake Kariba is a tropical lake with slight variations in seasonal temperature. Temperature is an important physical variable in the biology of both fish and their parasites. Currently, there is no information on the seasonal occurrence of fish parasites in Lake Kariba. The objective of this study was to investigate the seasonal occurrence of metazoan parasites in Hydrocynus vittatus in Lake Kariba, Zimbabwe. Twenty fish specimens were collected by seine netting per season between October 2014 and July 2015 in the Sanyati Basin, Lake Kariba, and examined for metazoan parasites. Mean water temperatures ranged from 24.1 °C to 31.2 °C with slight variations between the seasons. Metazoan parasites consisting of Monogenea (Annulotrema pikei, Annulotrema pseudonili, Annulotrema bracteatum), Nematoda (Contracaecum larvae), Copepoda (Lamproglena hemprichii), Cestoda (larval cestodes, Ichthybothrium sp.) and Pentastomida (pentastomid larvae) were recorded. Larval cestodes were recorded in autumn and spring, while pentastome larvae were recorded in summer and spring. The Ichthybothrium sp. was recorded once in winter. Annulotrema pikei and A. pseudonili were observed on the gills and A. bracteatum on both the gills and the skin. Contracaecum larvae, L. hemprichii and A. bracteatum (from the skin) were recorded in all the seasons, with slight variations in prevalence, mean abundance and mean intensity. However, these variations were not statistically significant (analysis of variance or ANOVA, p > 0.05). The slight variations in occurrence of the parasites were probably because of the thermal stability of the lake where variation in temperature was small between seasons. Both A. bracteatum and Contracaecum larvae were aggregated on the fish host, whereas L. hemprichii exhibited a random distribution. Parasite diversity was at its highest during winter.

Lake Kariba is a tropical lake with slight variations in seasonal temperature. Temperature is an important physical variable in the biology of both fish and their parasites. Currently, there is no information on the seasonal occurrence of fish parasites in Lake Kariba. The objective of this study was to investigate the seasonal occurrence of metazoan parasites in Hydrocynus vittatus in Lake Kariba, Zimbabwe. Twenty fish specimens were collected by seine netting per season between October 2014 and July 2015 in the Sanyati Basin, Lake Kariba, and examined for metazoan parasites. Mean water temperatures ranged from 24.1 °C to 31.2 °C with slight variations between the seasons. Metazoan parasites consisting of Monogenea (Annulotrema pikei, Annulotrema pseudonili, Annulotrema bracteatum), Nematoda (Contracaecum larvae), Copepoda (Lamproglena hemprichii), Cestoda (larval cestodes, Ichthybothrium sp.) and Pentastomida (pentastomid larvae) were recorded. Larval cestodes were recorded in autumn and spring, while pentastome larvae were recorded in summer and spring. The Ichthybothrium sp. was recorded once in winter. Annulotrema pikei and A. pseudonili were observed on the gills and A. bracteatum on both the gills and the skin. Contracaecum larvae, L. hemprichii and A. bracteatum (from the skin) were recorded in all the seasons, with slight variations in prevalence, mean abundance and mean intensity. However, these variations were not statistically significant (analysis of variance or ANOVA, p > 0.05). The slight variations in occurrence of the parasites were probably because of the thermal stability of the lake where variation in temperature was small between seasons. Both A. bracteatum and Contracaecum larvae were aggregated on the fish host, whereas L. hemprichii exhibited a random distribution. Parasite diversity was at its highest during winter.