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At least 19 recordsLinked to original sources
PubMed1979

Tick infestations and tick-borne diseases in Zimbabwe Rhodesia.

The distribution of tick species in Zimbabwe Rhodesia is significantly influenced by land utilization practices. The most commonly occurring species in the over-grazed tribal areas is Boophilus decoloratus. By contrast, well-managed commercial farms and ranches support a wide range of tick species, the most important of which is Rhipicephalus appendiculatus. Until recently tick-borne diseases of cattle were efficiently controlled through dipping. The low incidence of disease was an important factor contributing to over-grazing in tribal areas. Between 1973 and 1978 political unrest resulted in a collapse of the dipping service in tribal areas. Populations of B. decoloratus built up and outbreaks of babesiosis and anaplasmosis occurred, normally between one and three years after the cessation of dipping. Reduced grazing pressure after the initial disease waves resulted in increased grass cover, allowing species such as R. appendiculatus and Amblyomma hebraeum to become re-established. Outbreaks of theileriosis and heartwater usually followed, decimating the already depleted herds. The heavy cattle mortality resulted from lack of immunity to tick-borne diseases, as a result of efficient disease control through dipping in previous years.

Animals↗
PubMed2026

Spatiotemporal patterns of Rift Valley fever virus in Africa: a retrospective genomic epidemiology and phylodynamic modelling study.

BACKGROUND: Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing outbreaks in humans and ruminants across Africa and the Arabian Peninsula. Originally restricted to the Great Rift Valley, RVFV has expanded geographically, prompting its classification by WHO as a pathogen of pandemic potential. We investigated the evolutionary and spatial dynamics of RVFV across Africa. METHODS: We used genomic data generated at the International Livestock Research Institute Nairobi genomic laboratory (BioProject PRJNA1106221) and combined with publicly available datasets retrieved from the National Center for Biotechnology (NCBI) GenBank nucleotide database. In retrieving RVFV genome sequences from the NCBI GenBank, we applied the search terms "Rift Valley fever virus segment L AND 6404[SLEN]", "Rift Valley fever virus segment M AND 3885[SLEN]", and "Rift Valley fever virus segment S AND 1520:1690[SLEN]" for L (Large), M (Medium), and S (Small) segments, respectively. For sequences without additional spatiotemporal information, we searched PubMed to extract the associated sequence metadata. We performed molecular clock analysis, phylogenetic inference, phylodynamic modelling (continuous phylogeographic reconstruction), and landscape phylogeography on the three RVFV genome segments (L, M, and S). We aimed to assess evolutionary rates, dispersal patterns, and environmental drivers. Focus was placed on lineage C, the most widely distributed variant. FINDINGS: The global dataset used in this study consisted of large (n=236), medium (n=237), and small (n=247), which were further filtered to exclude potential reassortants and vaccine strains. Genome sequences retrieved from NCBI GenBank database comprised large (n=180), medium (n=184), and small (n=202). The genome sequences from retrospective human and livestock isolates comprised large (n=56), medium (n=53), and small (n=45) collected in Burundi (2018), Kenya (2007, 2018, 2019, 2021, and 2022), and Rwanda (2018 and 2022). Our dataset revealed that RVFV exhibited low overall genetic diversity. Lineage C, however, showed evidence of active evolution, with substitution rates ranging from 3·58 × 10-4 to 9·76 × 10-4 substitutions per site per year. This lineage probably originated in Zimbabwe in the mid-1970s and has since expanded across eastern and southern Africa. Phylogeographic reconstructions revealed rapid spread, with diffusion coefficients exceeding 50 000 km2 per year. INTERPRETATION: Lineage C appears capable of establishing endemic transmission in new regions, with ongoing diversification observed during interepidemic periods. These observations reinforce the value of continuous genomic surveillance, particularly during cryptic transmission phases when adaptive mutations might emerge. Although further evidence is needed, observed trends in climate variability and land-use change point to the potential benefit of targeted surveillance in settings that could be at increased risk, including urban centres and wetlands. FUNDING: This work was supported by the German Federal Ministry for Economic Cooperation and Development, the Rockefeller Foundation, and the Africa Centres for Disease Control and Prevention.

Rift Valley fever virus↗
PubMed2026

Changes in sexual behavior among women in studies evaluating the dapivirine vaginal ring for HIV prevention.

BACKGROUND: Access to novel HIV prevention technologies often raise concerns of risk compensation. This analysis examined changes in the sexual behaviors of MTN 020/ASPIRE participants, a placebo controlled randomized control trial, who subsequently enrolled in MTN-025/HOPE, an open-label extension using the dapivirine vaginal ring. METHODS: Both studies enrolled healthy, sexually active, HIV-negative women from Malawi, South Africa, Uganda and Zimbabwe. Longitudinal data on participants' sexual behaviors, specifically sex with a nonprimary partner (past 3&#xa0;months), and use of male or female condoms at the last vaginal sex act were compared between ASPIRE and HOPE. Conditional and mixed ordinal logistic regression models evaluated associations between study and sexual behaviors at enrollment,&#xa0;and quarterly over the first 12&#xa0;months. RESULTS: Of the 2629 individuals enrolled in ASPIRE, 1456 (55%) participated in HOPE. At enrollment, the proportion of participants who reported sex with a nonprimary partner and condom use at last vaginal sex act did not differ by study. Across all quarterly follow-up visits, sex with a nonprimary partner was more common in HOPE (13.9-18.7%) than ASPIRE (10.7-12.6%); adjusted OR&#xa0;1.47, 95% CI 1.24-1.75, P&#xa0;<&#xa0;0.001. There was no difference in condom use at the last vaginal act across all quarterly follow-up visits between ASPIRE (36.5-42.7%) and HOPE (43.6-46.7%); adjusted OR&#xa0;1.05, 95% CI 0.94-1.18. CONCLUSION: More women reported sex with nonprimary partners in HOPE, with little change in condom use over time between the two studies. Understanding behavior changes during PrEP use allows for tailored, holistic reproductive health programming.

Humans↗
PubMed2026

Characterisation of HIV-1 Gag Cytotoxic T-Lymphocyte Epitopes in the Southern African Region-A Systematic Review.

During early HIV-1 infection, robust Cytotoxic T-lymphocyte (CTL) responses are mostly targeted at immunodominant Gag p24 epitopes to reduce HIV-1 viraemia to a set-point. The aim of this study was to review the current body of knowledge on HIV-1 Gag CTL epitopes in the southern African region where subtype C is prevalent. Peer-reviewed records were obtained from three databases: PubMed Central, Web of Science Core Collection, and Scopus, using the following search terms: HIV subtype C Gag epitopes, and HIV clade C Gag epitopes. The search results were restricted to countries within the southern African region, and only data published in English and between the years 2000-2025 were considered for this review. The search from the three databases produced a total of 2103 peer-reviewed records, and 49 records were included in the review. The majority of studies (58.44%) were conducted in South Africa, followed by Botswana (15.58%), Zambia (10.39%), Malawi (7.79%), Zimbabwe (6.49%) and Angola (1.30%). There were no studies identified from other southern African countries. A total of 60 Gag CTL epitopes were identified, of which 17 (28.33%) were located within the matrix protein (p17), 33 (55.00%) within the capsid protein (p24), and 4 (6.67%) within the Gag polyprotein (p2p7p1p6). The commonly detected immunodominant epitopes were mostly located within the Gag p24 protein; and included TPQDLNTML (TL9, Gag p24 48-56) and TSTLQEQIGW (TW10, Gag p24 108-117) present at 16.00% and 13.3%, respectively. The proportion of HLA-A, B and C allotypes in this systematic review were 18%, 78%, and 4%, respectively. The more common HLA-B allotypes that restrict immunodominant Gag epitopes and facilitate better control of HIV-1 were HLA-B*57, -B*58:01, -B*42:01 and -B*81:01. This systematic review has provided important insights into the description of immunodominant Gag epitopes and HLA-I alleles that contribute to the control of HIV-1 viraemia in the southern African region. It has also exposed that some CTL epitopes identified in the southern African studies are not reported on the Los Alamos HIV database (LANL HIV database). This highlights a need to have this database updated with this information as it is used as a reference for epitopes. This review could provide insights into the design of an epitope-based HIV-1 vaccine that would also be effective in the southern African region.

Humans↗
PubMed1977

Hepatocellular carcinoma in the Rhodesian African.

We have carried out a prospective survey of 28 primary liver carcinomas over one year. Hepatocellular carcinoma is the commonest malignancy seen in Rhodesian blacks, which results in a high index of suspicion and accounts for the 96.4% positive diagnosis before death in this study. The age distribution was evenly spread through adult life with no definite peak incidence. Some were young and without evidence of chronic liver disease, but many had the stigmata of established hepatic disease. This contrasts with the common assertion that in areas of high incidence for primary liver cancer those affected are mainly young and lack signs of chronic liver disease. The commonest presenting symptoms were abdominal pain and swelling and weight loss. Hepatomegaly, often tender and nodular, was present in all but one. The incidence of alpha-feto protein, 46.5%, is low compared with other countries where primary liver cancer is common. Hepatitis B antigen was absent in all 28, suggesting that there is no association between the persistence of the antigen and hepatocellular carcinoma in Rhodesia. Liver function tests, although abnormal, were never diagnostic of primary liver cancer. We have confirmed the association of high alcohol consumption and cirrhosis with hepatocellular carcinoma.

Adult↗
PubMed1977

Insecticides, polychlorinated biphenyls and metals in African lake ecosystems. I. Hartbeespoort Dam, Transvaal and Voëlvlei Dam, Cape Province, Republic of South Africa.

Concentrations and distribution of chlorinated hydrocarbon insecticides, polychlorinated biphenyls (PCB's) and some metals were determined in two South African lakes, Hartbeespoort Dam and Voëlvlei Dam. Water, bottom sediments, aquatic plants, aquatic insects, fish, fish-eating birds and their eggs were collected. Insecticides and PCB's were analyzed by thin layer and gas chromatography and mass-spectrometry. Analysis of metals was accomplished with atomic absorption spectrophotometry. Metals included arsenic, cadmium, copper, mangenese, lead, zinc, and mercury. The insecticide residue most commonly found in both dams were DDE, DDD, DDT, and dieldrin. Hartbeespoort had higher levesl than Voëlvlei of insecticides and PCB's in all types of samples common to both lakes. Concentrations of PCB's in all types of samples common to both lakes. Concentrations of PCB's having six or more chlorines increased with an increase in the trophic level. Concentrations of PCB's in the brains of the African birds were greater than the average total concentration of insecticides while the opposite was true for carcasses. Biological magnification of insecticides and PCB's occurred in both lakes. Hartbeespoort Dam had higher levels than Voëlvlei for all metals examined in bottom sediments and birds, except for copper in bird carcasses. Mercury levels in bird carcasses ranged from 2- to 5-fold greater than in fish while lead concentrations ranged from 2- to 10-fold greater.

Animals↗
PubMed1976

Normal values for ventilatory function in Rhodesian Africans.

Forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow were measured in 141 African men and 102 African women aged 20 and above. Prediction formulae relating each measurement to height and age were drawn up and are presented. Rhodesian Africans have lower values for these measurements than subjects in some Europen and North American series, but broadly similar values to those of Africans elsewhere.

Adult↗
PubMed1975

Serum alpha-feto protein (alpha-FP) and hepatoma in Rhodesian Africans.

Alpha-feto protein (alpha-FP) is now accepted as a very useful serum marker of hepatocarcinoma, and since its discovery in 1963, surveys have been carried out in various regions of the world, where hepatoma is particularly prevalent, which have shown that alpha-FP may be detected in 50 to 80% of patients with liver cancer. The sera of 30 Rhodesian African patients with histologically proven hepatoma were tested in this study for the presence of alpha-FP. In only 47% was alpha-FP detected. Thus it is our experience that a positive result is strong evidence in favour of a diagnosis of hepatocarcinoma whilst a negative result is of little value, necessitating that liver biopsy be carried out in all patients with clinical suspicion of liver cancer.

Adolescent↗
PubMed1976

Amoebic liver abscess in Rhodesian Africans.

Eighty-eight African patients with amoebic liver abscess are described. The diagnosis was readily made in pyrexial patients who had right-sided upper abdominal pain, an enlarged, very tender liver and signs at the right base. However, in apyrexial subjects (10%) and where abdominal pain was absent (7%), the diagnosis was considerably delayed. Five children (7%) were seen under the age of five, four of whom died because the diagnosis was not suspected. It is particularly emphasized that there should be a greater awareness of this condition in this age group. Amoebae were found in only a small percentage of stool (14%) and pus specimens (11%), while biopsy of the abscess edge yielded 40%. The relative values of a positive amoebic latex test (82%) and an elevated alkaline phosphatase (71%) are noted. In only half the aspirations was the classical anchovy sauce appearance seen. Metronidazole is the drug of choice with repeated aspirations for large abscesses. Mortality was 13-5%, occurring mainly in the extremes of life.

Adolescent↗