Association of NS1 Antigen, IgM, IgG Antibodies and RT-PCR in the Diagnosis of Dengue Virus Infection

Background: To determine the association of ELISA based serological markersNS1 antigen, IgM, IgG antibodies and RT-PCR in the diagnosis of dengue virus infection Methods: In this descriptive cross sectional study 420 serum samples from patients with suspicion of dengue fever were tested for detection of dengue by NS1 antigen ELISA, IgG, IgM ELISA. RT-PCR for dengue was carried out in all NS1 antigen ELISA positive cases for confirmation of dengue. Results: Out of 420 cases , 249 cases were positive for either one of the three markers NS1, IgM,IgG. Males constituted 71.66%.Two hundred and two (48.09%) were positive for NS1 only,13 (3.09%) were positive for NS1 and IgG, 07 (1.66%) were NS1, IgM and IgG positive,16 (3.80%) were positive for IgG only ,11 (2.61%) were positive for NS1 and IgM whereas 171 (40.17%) samples were reported negative for NS1, IgM and IgG.RT-PCR was conducted on 233 NS1 positive cases out of which 80.06% cases turned out positive. Maximum number of cases belonged to DEN-2 genotype. Conclusion: Early diagnosis helps in improved patient care, suitable treatment, prevents severe complications and helps limit the spread of the disease. RT PCR is  a reliable test for the  diagnosis of acute dengue fever

Epidemiological analysis of emerging and re-emerging virus infections in Mozambique

Background Emerging and re-emerging viral infections are an increasing important concern for global public health. Previous studies conducted in Mozambique have shown occurrence of several emerging virus infections, including arbovirus. However, existing evidence on arbovirus is not recent and no data exists on co-occurrence of arbovirus and malaria. Besides, the ongoing COVID-19 pandemic hit Mozambique since March 2020, causing until mid-2021 three waves. There is a lack of an in-depth characterization of the epidemiologic profile of COVID-19 in Mozambique. Methods Samples from acute febrile patients selected retrospectively (2009 to 2015) and prospec-tively (2017 a 2018) were screened for Dengue, Chikungunya and Zika virus using com-mercially available ELISA. Additionally, we reviewed records of suspected and con-firmed cases of COVID-19 collected in 11 provinces of Mozambique between March 2020 to September 2021. All of confirmed COVID-19 cases were subsequently mapped. Results From the 895 retrieved samples, the positive samples we found 54 (6.0%) were IgM an-ti-CHIKV, 160 (17.8%) positive for IgG anti-CHIKV, 16/577 (2.8%) for DENV-NS1. And IgM anti-ZIKV were also found in 42/850 (4.9%). For the prospective approach, of the 906 participants, the positive frequency was as follow 134 (14.8%) for IgM anti-CHIKV, 332 (36.6%) for IgG anti-CHIKV, 64 (7.1%) for IgM anti-DENV, 16 (1.8%) NS1-DENV and 83 (9.2%) for IgM anti-ZIKV. Malaria was diagnosed in 56 (6.2%) participants, 16 (1.1%) of whom were also IGM-positive for CHIKV, 3 (5.4%) for DENV-IgM and 10 (0.4%) for ZIKV. Regarding COVID-19, a total 778,926 individuals were screened for SARS-CoV-2 using Rt-PCR real time and Ag-RDT between 22 March 2020 and 30 September 2021, of whom (17.8%; 138,468/778,926) returned positive. The number of cas-es was increased by more than 60,000 from the first to the third wave of COVID-19 pan-demicand the Chi-square test revealed significant differences between the three waves (p<0.01). Conclusion This study represents the largest serological study of arbovirus in febrile patients con-ducted in Mozambique. The results from this study indicate that first: for several years CHIKV, DENV and ZIKV have silently circulated and the Mozambicans across all prov-inces. And second, that co-occurrence between malaria and CHIKV, DENV and ZIKV among febrile patients is more common than previously thought. In addition, our analysis also describes the three waves of COVID-19 in Mozambique. The findings raise the need for increased awareness of arboviral infection as another cause of acute febrile illness and recommend active surveillance of viral emerging diseases to improve human public health

Interfering with interferon: developing a reporter system to study the interaction between hepatitus C viral proteins and the interferon signalling pathway

PhDThe aim of the project was to investigate the mechanism by which HCV evades therapeutic IFN treatment. This involved the development of novel testing systems and their application to patient samples. Initial experiments focused on flavivirus replicons and novel observations on effects of one of these replicons (dengue virus) on interferon signalling were made. The dengue replicon system was demonstrated to inhibit IFNa signalling by reducing the expression of STAT2, an essential component of the type I IFN signalling pathway. This phenomenom was then further examined in dengue virus infected human cells and again it was observed that the expression of STAT2 was reduced. The mechanism of STAT2 degradation was further explored and STAT2 expression was found to be restored using a proteasomal inhibitor. A second flavivirus replicon system involving BVDV was also developed as a reporter system, again with novel observations. The BVDV replicon system was shown to be sensitive to the antiviral effects of I FNa and was not shown to inhibit the IFNa signalling pathway. The BVDV replicon was tested as a reporter system using a well-known viral inhibitor of I FNa. The viral inhibitor, inhibited the antiviral action of IFNa on the BVDV reporter. Having developed and validated this system, the effects of a small number of patient derived samples were assessed and it was demonstrated that NS5a derived from a patient who failed to respond to IFNa treatment inhibited the effects of IFNa on the BVDV reporter. To increase the senstitivity of the assay the reporter cassette was then changed to a destabilised GFP for use in a FACS based assay