Viral Epitope Scanning Reveals Correlation between Seasonal HCoVs and SARS-CoV-2 Antibody Responses among Cancer and Non-Cancer Patients.

Seasonal coronaviruses (HCoVs) are known to contribute to cross-reactive antibody (Ab) responses against SARS-CoV-2. While these responses are predictable due to the high homology between SARS-CoV-2 and other CoVs, the impact of these responses on susceptibility to SARS-CoV-2 infection in cancer patients is unclear. To investigate the influence of prior HCoV infection on anti-SARS-CoV-2 Ab responses among COVID-19 asymptomatic individuals with cancer and controls without cancers, we utilized the VirScan technology in which phage immunoprecipitation and sequencing (PhIP-seq) of longitudinal plasma samples was performed to investigate high-resolution (i.e., epitope level) humoral CoV responses. Despite testing positive for anti-SARS-CoV-2 Ab in the plasma, a majority of the participants were asymptomatic for COVID-19 with no prior history of COVID-19 diagnosis. Although the magnitudes of the anti-SARS-CoV-2 Ab responses were lower in individuals with Kaposi sarcoma (KS) compared to non-KS cancer individuals and those without cancer, the HCoV Ab repertoire was similar between individuals with and without cancer independent of age, sex, HIV status, and chemotherapy. The magnitudes of the anti-spike HCoV responses showed a strong positive association with those of the anti-SARS-CoV-2 spike in cancer patients, and only a weak association in non-cancer patients, suggesting that prior infection with HCoVs might play a role in limiting SARS-CoV-2 infection and COVID-19 disease severity.

Clinicopathological Characteristics and Outcomes of Anal Squamous Cell Carcinoma Patients With and Without HIV Infection in Sub-Saharan Africa.

PURPOSE: In the past 20 years, the burden of anal cancer (AC) increased by 60% in the United States and over three-fold in Africa. Rates of AC have increased by 20× in people living with HIV and the highest (50×) in men with HIV who have sex with men. However, in sub-Saharan Africa (SSA) where HIV is endemic, data on clinicopathological characteristics and outcomes of patients with AC are lacking. To address this, we have investigated AC disease presentation, treatment outcomes, and its predictors in a cohort of patients who were either HIV-infected or HIV-uninfected in SSA. METHODS: We conducted a retrospective cohort study of patients with anal squamous cell carcinoma (SCC) treated at Ocean Road Cancer Institute in Dar es Salaam, Tanzania from January 2014 to December 2019. Associations between the study outcomes and their predictors were analyzed using univariate and multivariate analysis models. RESULTS: A total of 59 patients with anal SCC were retrieved and had at least 2-year follow-up. The mean age was 53.9 (standard deviation ±10.5) years. While none of the patients presented with stage I disease, 64.4% had locally advanced disease. HIV infection was the major comorbidity (64.4%). The rate of complete remission at the end of treatment was at 49% while the 2-year overall survival (OS) and local recurrence-free survival were 86.4% and 91.3%, respectively. Despite high HIV coinfection in the cohort, AC treatment outcomes were not significantly associated with HIV status. Disease stage (P = .012) and grade (P = .030) were significantly associated with 2-year OS. CONCLUSION: Patients with anal SCC in Tanzania present mainly with locally advanced disease associated with high HIV prevalence. In this cohort, the SCC grade was independently associated with treatment outcomes unlike other factors such as HIV coinfection.

Lower SARS-CoV-2 Seroprevalence among Cancer Patients in Sub-Saharan Africa.

BACKGROUND: Despite the high COVID-19 morbidity and mortality rates across the world, the reported rates in sub-Saharan Africa (SSA), which has a higher burden of other infectious diseases and overwhelmed healthcare systems, remain relatively low. This study aims to better understand the potential factors that contribute to this phenomenon, especially among cancer patients who are considered as a high-risk group for developing severe COVID-19. METHODS: Plasma samples collected during the COVID-19 pandemic from SARS-CoV-2 unvaccinated cancer and potential blood donor populations were analyzed for SARS-CoV-2 (spike and nucleocapsid proteins) antibodies by an immunofluorescence assay. The relationships between SARS-CoV-2 seroprevalences and study variables were determined using a logistic regression analysis. RESULTS: High seroprevalence against the SARS-CoV-2 spike and nucleocapsid proteins were found among the SARS-CoV-2 unvaccinated COVID-19 pandemic populations in SSA. However, the cancer patients demonstrated a lower seroprevalence compared to potential blood donors. There was also an association between mild COVID-19 symptoms with prior tuberculosis vaccination among cancer patients. CONCLUSION: Cancer patients in SSA tend to have a relatively lower SARS-CoV-2 seroprevalence compared to potential blood donors recruited from the same geographic locations during the COVID-19 pandemic. More study is required to determine its cause and potential impact on SARS-CoV-2 vaccination among cancer patients.

DNA barcoding and delimitation of critically endangered indigenous and introduced tilapias (pisces cichlidae) of Pangani catchment, Northern Tanzania.

The Pangani catchment of Northern Tanzania harbours the critically endangered endemic tilapias of the genus Oreochromis. The introduction of non-native congenerics and consequent hybridization complicates taxa identification and phylogeny based on morphological systematics. We therefore morphologically and molecularly identified these tilapias and delimited their Molecular Operational Taxonomic Units (MOTUs) based on Cytochrome Oxidase Subunit I (CO1) gene for future management and conservation. A total of 132 indigenous and introduced tilapia specimens were morphologically identified, barcoded using the CO1 gene and delimited by Kimura 2 Parameter distance approaches, Automatic Barcode Gap Discovery (ABGD), Neighbour Joining (NJ) tree and haplotype analysis. Theoverall mean conspecific, congeneric and confamillial genetic distances based on the K2P model were 0.54%, 5.32% and 13.29% respectively. All taxa had a mean K2P distance < 2% and 90% (n = 10), were clearly delimited by the ABGD method. The NJ tree delimited tilapia taxa commensurate to the genetic distances depicted by DNA barcoding. However, DNA barcoding and NJ tree coherently failed to discriminate the morphologically distinct allopatric Oreochromis jipe and Oreochromis hunteri taxa. Moreover, the two methods depicted lack of monophyly in Oreochromis korogwe MOTUs implying that the taxon could consist of at least one MOTU. We conclude that the integration of morphological-based taxonomy and DNA barcoding among ichthyofaunal taxa herein will be invaluable in conservation and management of native tilapias in Pangani basin.

Detection of Porcine Cysticercosis in Meat Juice Samples from Infected Pigs.

BACKGROUND: Seroprevalence of porcine cysticercosis has been generally studied using enzyme-linked immunosorbent assays (ELISA) detecting either antigens or antibodies in sera. However, serum is not always readily available. The objective of this study was to assess the diagnostic potential of meat juice in detecting porcine cysticercosis using a cysticercosis antibody ELISA. METHODS: Sera and meat juice samples from 13 different organs/tissues were collected from nine pigs naturally infected with cysticercosis and from six uninfected pigs reared under hygienic conditions. The sensitivity of the cysticercosis antibody ELISA in detecting porcine cysticercosis in meat juice samples was compared to that in serum samples from the same pigs. RESULTS: Using sera, cysticercosis was detected in all nine pigs harbouring cysticerci, but not in those reared under hygienic conditions. The sensitivity of the ELISA was highest in meat juice extracted from the diaphragm (100%), heart (89%) and neck muscle (78%) of the nine infected pigs, whereas it varied between 0 and 44% in the other samples. CONCLUSION: To the best of our knowledge, this is the first study for T. solium cysticercosis serology to use meat juice. Our results show that meat juice from pig carcass organs or muscles is a promising diagnostic specimen for the detection of porcine cysticercosis. More studies including a large sample size of pigs with varying degrees of cysticercosis infection are needed to further prove this concept.

Soil contamination by Taenia solium egg DNA in rural villages in Kongwa district, Tanzania.

The presence ofTaenia solium DNA from eggs in soils around the households in four Tanzanian villages in Kongwa district were analysed in relation to seasonal fluctuations and infection risk implications. A total of 192 pooled soil samples from five sampling points per household were examined by droplet digital Polymerase Chain Reaction (ddPCR) from 96 pig-keeping households both during the dry and rainy seasons. The pooled samples were first processed by a flotation-double sieving technique, followed by screening for worm DNA employing universal primers targeting the mitochondrial cytochrome c oxidase subunit I (cox1) gene of human taeniid species and some other helminths. All DNA positive samples were later confirmed by a specific ddPCR probe assay targeting the mitochondrial cox1 gene of T. solium. A total of 17.2% (n = 33) samples were positive with the universal ddPCR, whereas T. solium DNA was confirmed by the specific ddPCR only in 3.1% (n = 3) of the surveyed households. The detection of T. solium DNA in this study spells out a low risk of exposure to T. solium eggs from contaminated household soil. Based on our results, ddPCR seems to be a promising technology for screening T. solium eggs in soil.

Seroprevalence of circulating taeniid antigens in pigs and associated risk factors in Kongwa district, Tanzania.

The aim of this study was to investigate exposure to porcine cysticercosis (PC) and associated risk factors in the Kongwa District, eastern-central Tanzania. For the first time a cross-sectional investigation of the seroprevalence in pigs using a commercial genus specific cysticercosis enzyme linked immunosorbent assay (apDia Ag-ELISA) was undertaken in eastern-central Tanzania. Moreover, the identity of suspected T. solium cysts from pigs in the study area were confirmed by sequencing parasites' mitochondrial cox1 gene. Structured questionnaires and direct observations were used to investigate risk factors associated with parasite transmission. A total of 102 pig-keeping households were surveyed during the dry season between July and August 2017 and 126 households in the rainy season between March and April 2018. Of the 447 examined pigs, 77 (17%, 95% C.I. 14%-20%) tested positive in the ELISA. Seroprevalence was higher in pigs examined during the rainy (21%, 95% C.I. 16%-26%) than dry (12%, 95% C.I. 7%-17%) season (p = 0.019). Eight cyst-positive-pigs were confirmed to be infected with T. solium by sequencing. Risk factors associated with PC seropositivity included origin of piglets or pigs (OR = 0.27, 95% C.I. 0.13-0.42, p = 0.001), socioeconomic factors and pig production system (OR = 0.22, 95% C.I. 0.07-0.37, p = 0.005) and sanitation and hygiene practices (OR = 0.19, 95% C.I. 0.04-0.34, p = 0.014). This study has recorded a high Taenia spp. seroprevalence in pigs in Kongwa suggesting the presence of people in the community carrying the adult parasite, Taenia solium. Our findings also suggest risk of infection by T. solium to people in urban centres and cities consuming pigs from rural areas in Kongwa. The high seroprevalence in Kongwa calls for further studies on taeniasis and cysticercosis in the human population in order to determine suitable control strategies.

Validation of droplet digital Polymerase Chain Reaction for the detection and absolute quantification of Taenia solium eggs in spiked soil samples.

To enable the detection of taeniid eggs in environmental samples, a sensitive technology is required. In this study, we validated the effectiveness of a digital droplet Polymerase Chain Reaction (ddPCR) assay for detection, identification and absolute quantification of taeniid DNA from artificially contaminated soils with varying numbers of taeniid eggs using a set of universal primers, JB3 & JB4.5. The results showed that the number of cox1 copies detected increased gradually for both species with the number of taeniid eggs added to the different soil types. The highest cox1 DNA copies recovery for Taenia solium and T. lynciscapreoli was from the sand soil with lowest recovery being observed in clay soils. Therefore, ddPCR is a promising technology for screening of taeniid eggs from soil samples collected in the environment irrespective of the soil type and the number of eggs. The potential of the ddPCR protocol to detect taeniid egg DNA in spiked soil samples has great practical application for taeniid egg screening in soils from endemic areas. However, when universal primers are used in screening environmental samples, the identity of ddPCR positive samples must be confirmed by sequencing. In addition, more validation studies using species-specific primers and field soil samples is recommended.

Fatty Acid composition and levels of selected polyunsaturated Fatty acids in four commercial important freshwater fish species from lake victoria, Tanzania.

Fatty acids (FAs) particularly ω3 and ω6 polyunsaturated fatty acids (PUFAs) play important role in human health. This study aimed to investigate the composition and levels of selected ω3 PUFAs in four commercial fish species, Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus), Tilapia zillii, and dagaa (Rastrineobola argentea) from Mwanza Gulf in Lake Victoria. The results indicated that 36 types of FAs with different saturation levels were detected. These FAs were dominated by docosahexaenoic (DHA), eicosapentaenoic (EPA), docosapentaenoic (DPA), and eicosatetraenoic acids. O. niloticus had the highest composition of FAs (34) compared to L. niloticus (27), T. zillii (26), and R. argentea (21). The levels of EPA differed significantly among the four commercial fish species (F = 6.19, P = 0.001). The highest EPA levels were found in R. argentea followed by L. niloticus and O. niloticus and the lowest in T. zillii. The DPA levels showed no significant difference among the four fish species studied (F = 0.652, P = 0.583). The study concluded that all four commercial species collected from Mwanza Gulf are good for human health, but R. argentea is the best for consumption because it contains higher levels of ω3 FAs, mainly EPA.

Determinants of the parasite community of clariid fishes from Lake Victoria, Tanzania.

The factors that determine parasite assemblages among the clariid fishes of Lake Victoria, Tanzania were studied between August 2003 and February 2005. Six hundred and fifty-six fish belonging to seven species were necropsied and examined for parasites, from which 31 species of metazoan parasites were recorded. The community was dominated by the nematodes both in species and numbers. Most species were generalists with only two trematodes, Diplostomum mashonense and Tylodelphys species, being specialists of Clarias gariepinus. Ten species were considered core and predictable. Parasite species richness, number of individuals per host and Shannon-Wiener diversity indices were generally high. At the compound community level, a mean number of 7.8 parasites were shared among different species of fish and the maximum number of parasites species per fish at the infracommunity level was seven. Levels of similarity in parasite species richness at the component community level ranged from 29.6 to 61.5%. The study concludes that parasite communities in clariid fishes of Lake Victoria are structured by ecological factors. At the infracommunity level, host size, diet and vagility promoted a richer parasite community. At the compound level, two factors were crucial, namely the intermixing of the waters in the lake and the predominant and mobile C. gariepinus.