Measles virus (MV) and canine distemper virus (CDV) are highly contagious and deadly, forming part of the morbillivirus genus. The receptor recognition by morbillivirus hemagglutinin (H) is important for determining tissue tropism and host range. Recent reports largely urge caution as regards to the potential expansion of host specificities of morbilliviruses. Nonetheless, the receptor-binding potential in different species of morbillivirus H proteins is largely unknown. Herein, we show that the CDV-H protein binds to the dog signaling lymphocyte activation molecule (SLAM), but not to the human, tamarin, or mouse SLAM. In contrast, MV-H can bind to human, tamarin and dog SLAM, but not to that of mice. Notably, MV binding to dog SLAM showed a lower affinity and faster kinetics than that of human SLAM, and MV exhibits a similar entry activity in dog SLAM- and human SLAM-expressing Vero cells. The mutagenesis study using a fusion assay, based on the MV-H–SLAM complex structure, revealed differences in tolerance for the receptor specificity between MV-H and CDV-H. These results provide insights into H-SLAM specificity related to potential host expansion.

The aim of the present study was to investigate the association of APOE, MTHFR and ACE polymorphisms with stroke in the Zambian population. We analyzed 41 stroke patients and 116 control subjects all of Zambian origin for associations between the genotype of the APOE, MTHFR and ACE polymorphisms and stroke. The APOE ε2ε4 genotype showed increased risk for hemorrhagic stroke (P<0.05) and also a high risk for ischemic stroke (P=0.05). There was complete absence of the APOE ε2ε2 and the MTHFR TT genotypes in the Zambian population. The difference between cases and controls was not significant for the other genetic variants when analyzed for relationship between stroke, stroke subtype and genotype. We show that genetic variation at the APOE locus affects susceptibility to stroke. No detectable association were observed for the MTHFR and ACE genotypes and stroke in the Zambian population.

BackgroundPolymorphisms within the apolipoprotein-E (APOE), Methylenetetrahydrofolate reductase (MTHFR) and Angiotensin I-converting enzyme (ACE) genes has been associated with cardiovascular and cerebrovascular disorders, Alzheimer’s disease and other complex diseases in various populations. The aim of the study was to analyze the allelic and genotypic frequencies of APOE, MTHFR C677T and ACE I/D gene polymorphisms in the Zambian population.ResultsThe allele frequencies of APOE polymorphism in the Zambian populations were 13.8%, 59.5% and 26.7% for the ε2, ε3 and ε4 alleles respectively. MTHFR C677T and ACE I/D allele frequencies were 8.6% and 13.8% for the T and D minor alleles respectively. The ε2ε2 genotype and TT genotype were absent in the Zambian population. The genetic distances between Zambian and other African and non-African major populations revealed an independent variability of these polymorphisms.ConclusionWe found that the APOE ε3 allele and the I allele of the ACE were significantly high in our study population while there were low frequencies observed for the MTHFR 677 T and ACE D alleles. Our analysis of the APOE, MTHFR and ACE polymorphisms may provide valuable insight into the understanding of the disease risk in the Zambian population.

BackgroundTo date, 43 types of Spinocerebellar Ataxias (SCAs) have been identified. A subset of the SCAs are caused by the pathogenic expansion of a CAG repeat tract within the corresponding gene. Ethnic and geographic differences are evident in the prevalence of the autosomal dominant SCAs. Few descriptions of the clinical phenotype and molecular genetics of the SCAs are available from the African continent. Established studies mostly concern the South African populations, where there is a high frequency of SCA1, SCA2 and SCA7. The SCA7 mutation in South Africa (SA) has been found almost exclusively in families of indigenous Black African ethnic origin.ObjectiveTo present the results of the first clinical description of seven Zambian families presenting with autosomal dominant SCA, as well as the downstream molecular genetic analysis of a subset of these families.MethodsThe study was undertaken at the University Teaching Hospital in Lusaka, Zambia. Ataxia was quantified with the Brief Ataxia Rating Scale derived from the modified international ataxia rating scale. Molecular genetic testing for 5 types of SCA (SCA1, SCA2, SCA3, SCA6 and SCA7) was performed at the National Health Laboratory Service at Groote Schuur Hospital and the Division of Human Genetics, University of Cape Town, SA. The clinical and radiological features were evaluated in seven families with autosomal dominant cerebellar ataxia. Molecular genetic analysis was completed on individuals representing three of the seven families.ResultsAll affected families were ethnic Zambians from various tribes, originating from three different regions of the country (Eastern, Western and Central province). Thirty-four individuals from four families had phenotypic features of SCA7. SCA7 was confirmed by molecular testing in 10 individuals from 3 of these families. The age of onset of the disease varied from 12 to 59 years. The most prominent phenotypic features in these families were gait and limb ataxia, dysarthria, visual loss, ptosis, ophthalmoparesis/ophthalmoplegia, pyramidal tract signs, and dementia. Affected members of the SCA7 families had progressive macular degeneration and cerebellar atrophy. All families displayed marked anticipation of age at onset and rate of symptom progression. The pathogenic SCA7 CAG repeat ranges varied from 47 to 56 repeats. Three additional families were found to have clinical phenotypes associated with autosomal dominant SCA, however, DNA was not available for molecular confirmation. The age of onset of the disease in these families varied from 19 to 53 years. The most common clinical picture in these families included a combination of cerebellar symptoms with slow saccadic eye movements, peripheral neuropathy, dementia and tremor.ConclusionSCA is prevalent in ethnic Zambian families. The SCA7 families in this report had similar clinical presentations to families described in other African countries. In all families, the disease had an autosomal dominant pattern of inheritance across multiple generations. All families disp...

No abstract

No abstract

Canine distemper virus (CDV) belongs to morbillivirus, including measles virus (MeV), which causes serious immunological and neurological disorders in carnivores, but their vaccines are highly effective. The attachment glycoprotein hemagglutinin (CDV-H) at the CDV surface utilizes signaling lymphocyte activation molecule (SLAM) and Nectin-4 as entry receptors. Although fusion models have been proposed, the molecular mechanism of morbillivirus fusion entry is poorly understood. Here, we determined the crystal structure of the globular head domain of CDV-H vaccine strain at 3.2 Å resolution, revealing that CDV-H exhibits a highly tilted homodimeric form with a six-bladed β-propeller fold. While the predicted Nectin-4 binding site is well-conserved with that of MeV-H, that of SLAM is similar but partially different, which contributes to host specificity. Five N-linked sugars covered a broad area of the CDV-H surface to expose receptor binding sites only, supporting the effective production of neutralizing antibodies. These features are common to MeV-H, although the glycosylation sites are completely different. Furthermore, real-time observation using high-speed atomic force microscopy revealed highly mobile features of the CDV-H dimeric head. These results suggest that sugar-shielded tilted-homodimeric structure and dynamic changes are common characteristics of morbilliviruses and ensure effective fusion entry and vaccination.

Background The World Health Organization targets to screen 70% of women worldwide twice for cervical cancer by the year 2030, first by age of 35, and again by the age of 45. However, with the current low screening coverage in many developing countries, this may not be achieved because the invasive sampling method is unacceptable to some. In Zambia, for instance, despite the availability of free cervical cancer screening through the establishment of the Cervical Cancer Prevention Programme, some women are still reluctant to go for screening. First void urine sampling is non-invasive and thus has the potential to increase screening coverage. We aimed to determine the performance of first void urine for high-risk human papillomavirus DNA detection, the prevalence of high-risk HPV, and the acceptability of first void urine sampling. Materials and method A comparative cross-sectional study was conducted among 100 HIV- infected women at St Francis’ Hospital in Zambia, attending the routine HIV/AIDS services and cervical cancer screening. 17 mL of first void urine sample collected by each participant was immediately mixed with 3 mL of 0.5 M EDTA preservative solution before cervical sample collection by the clinician. For testing, 2 mL of first void urine and 1 mL of the cervical sample were tested using the GeneXpert platform. An interview-based questionnaire was used to gather data on the acceptability of first void urine sampling. Data was analyzed using Stata version 17. Results The mean age of the participants was 42.58 years (95% CI 40.98–44.19; SD 8.01). High-risk HPV prevalence was 34% (95% CI 24%-43.9%) in both cervical and first void urine samples. Sensitivity and specificity were 84.8% (95% CI 68.1%–94.9%) and 92.3% (83%–97.5%), respectively. There was 89.80% agreement between the samples (κ = 0.77; 95% CI 0.64–0.91). First void urine sampling was highly accepted. Conclusion High-risk HPV DNA can be detected in first void urine samples using the GeneXpert, with a substantial agreement with cervical samples. An affordable preservative such as Ethylenediamine tetraacetic acid can prevent DNA degradation. With optimization, first void urine sampling has the potential to increase screening coverage.