Dengue Virus Serotype 2 Established in Northern Mozambique (2015-2016).

After the report of an outbreak of dengue virus serotype 2 in 2014 in Nampula and Pemba cities, northern Mozambique, a surveillance system was established by the National Institute of Health. A study was performed during 2015-2016 to monitor the trend of the outbreak and confirm the circulating serotype of dengue virus (DENV). After the inclusion of consenting patients who met the case definition, samples from 192 patients were tested for the presence of nonstructural protein 1 antigen, and 60/192 (31%) samples were positive. Further analysis included DENV IgM antibodies, with 39 (20%) IgM positive cases. Reverse transcriptase (RT) PCR was performed for identification of the prevailing DENV serotype; 21/23 tested samples were DENV-2 positive, with DENV-2 present in both affected cities. When sequencing DENV, phenotype Cosmopolitan was identified. The surveillance indicates ongoing spread of DENV-2 in northern Mozambique 2 years after the first report of the outbreak.

Epidemiological aspects and microbiological characterization of fevers among residents of mozambique and swedish travellers returning from the tropics

The common theme and aim for this thesis was to explore the epidemiology and the diagnostic possibilities of patients with non-malarial febrile infections of tropical origin, with both the individual patient perspective and the more general public health aspects in focus. Analysis from two study areas, Sweden and Mozambique, are presented in the project. The infectious disease panorama in Mozambique has to a large extent been a blind spot. Further epidemiological studies, aiming at more knowledge to guide decisions on preventive measures, are needed. We performed two prospective investigations. The first one was a pilot sero-epidemiological study on vector-bomne viral zoonoses, in which we screened serum samples from patients attending a health care clinic in the suburb of the capital Maputo. In the analysis we found that 29% of the patients screened had an antibody response against one or more of the viral pathogens. Our conclusion, based on these results, was that exposure to chikungunya virus (CHIKV), dengue virus (DENV) and Rift Valley fever virus (RVFV) had taken place, and that these viruses are circulating 1n the country. The second study was an Investigation of the DENV outbreak in the cities Pemba and Nampula. We analysed serum samples for DENV by PCR from patients seeking medical attention for fever during 2015- 2016. The results including PCR positive samples, serotyping and sequencing of strains, confirmed that DENV serotype 2 is now endemic in northem Mozambique. In the Swedish multicentre study we prospectively included febrile travellers returning to Sweden from tropical areas defined as malaria endemic. Epidemiological data from questionnaires and clinical diagnoses given to patients by their attending doctors were first compared with results from a panel of extended laboratory diagnostics, primarily on convalescent samples. We then focused on the possibilities for early diagnostics with PCR, particularly for cases where no relationship between the febrile illness and a microbial pathogen had been identified. We also developed a universal PCR for diagnosis of early phase DENV infection. This universal single probe real time RT-PCR for DENV was then used for the DENV analysis on acute samples. The results showed that infectious disease clinicians in Sweden, when taking care of febrile travellers returning from the tropics, were in general able to establish a diagnosis based on laboratory diagnostics for relevant pathogens. That being said, we also noted that 30 % of the patients included in the study were dismissed with the diagnosis fever of unknown origin. It was also apparent from the results that influenza virus infection was a frequent, and often missed, diagnose among febrile travellers, regardless of the time of year. The antibody screening also identified several additional cases of dengue infection. When including the PCR for DENV in the diagnostic kit, it was possible to reduce even further the number of cases with diagnosis of unknown fever. This confirms that the universal PCR for DENV is a sensitive, specific and valuable diagnostic tool to use during the first 5 days in the acute phase of iliness. Apart from influenza and DENV, Rickettsia and Leptospira infections stood out as differential diagnoses that needed to be addressed.

Dengue Virus Serotype 2 Established in Northern Mozambique (2015­2016)

After the report of an outbreak of dengue virus serotype 2 in 2014 in Nampula and Pemba cities, northernMozambique, a surveillance system was established by the National Institute of Health. A study was performed during2015­2016 to monitor the trend of the outbreak and confirm the circulating serotype of dengue virus (DENV). After theinclusion of consenting patients who met the case definition, samples from 192 patients were tested for the presence ofnonstructural protein1antigen,and60/192(31%)sampleswerepositive.FurtheranalysisincludedDENVIgMantibodies,with 39 (20%) IgM positive cases. Reverse transcriptase (RT) PCR was performed for identification of the prevailing DENVserotype; 21/23 tested samples were DENV-2 positive, with DENV-2 present in both affected cities. When sequencingDENV, phenotype Cosmopolitan was identified. The surveillance indicates ongoing spread of DENV-2 in northernMozambique 2 years after thefirst report of the outbreak.

Universal single-probe RT-PCR assay for diagnosis of dengue virus infections.

BACKGROUND: Dengue is a mosquito-borne viral disease that has become more prevalent in the last few decades. Most patients are viremic when they present with symptoms, and early diagnosis of dengue is important in preventing severe clinical complications associated with this disease and also represents a key factor in differential diagnosis. Here, we designed and validated a hydrolysis-probe-based one-step real-time RT-PCR assay that targets the genomes of dengue virus serotypes 1-4. METHODOLOGY/PRINCIPAL FINDINGS: The primers and probe used in our RT-PCR assay were designed to target the 3' untranslated region of all complete genome sequences of dengue virus available in GenBank (n = 3,305). Performance of the assay was evaluated using in vitro transcribed RNA, laboratory-adapted virus strains, external control panels, and clinical specimens. The linear dynamic range was found to be 104-1011 GCE/mL, and the detection limit was between 6.0×102 and 1.1×103 GCE/mL depending on target sequence. The assay did not cross-react with human RNA, nor did it produce false-positive results for other human pathogenic flaviviruses or clinically important etiological agents of febrile illnesses. We used clinical serum samples obtained from returning travelers with dengue-compatible symptomatology (n = 163) to evaluate the diagnostic relevance of our assay, and laboratory diagnosis performed by the RT-PCR assay had 100% positive agreement with diagnosis performed by NS1 antigen detection. In a retrospective evaluation including 60 archived serum samples collected from confirmed dengue cases 1-9 days after disease onset, the RT-PCR assay detected viral RNA up to 9 days after appearance of symptoms. CONCLUSIONS/SIGNIFICANCE: The validation of the RT-PCR assay presented here indicates that this technique can be a reliable diagnostic tool, and hence we suggest that it be introduced as the method of choice during the first 5 days of dengue symptoms.

The cost-effectiveness of introducing nucleic acid testing to test for hepatitis B, hepatitis C, and human immunodeficiency virus among blood donors in Sweden.

BACKGROUND: The purpose of this study was to estimate the cost-effectiveness of using individual-donor nucleic acid testing (ID-NAT) in addition to serologic tests compared with the sole use of serologic tests for the identification of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) among blood donors in Sweden. STUDY DESIGN AND METHODS: The two strategies analyzed were serologic tests and ID-NAT plus serologic tests. A health-economic model was used to estimate the lifetime costs and effects. The effects were measured as infections avoided and quality-adjusted life-years (QALYs) gained. A societal perspective was used. RESULTS: The largest number of viral transmissions occurred with serologic testing only. However, the risks for viral transmissions were very low with both strategies. The total cost was mainly influenced by the cost of the test carried out. The cost of using ID-NAT plus serologic tests compared to serologic tests alone was estimated at Swedish Krona (SEK) 101 million (USD 12.7 million) per avoided viral transmission. The cost per QALY gained was SEK 22 million (USD 2.7 million). CONCLUSION: Using ID-NAT for testing against HBV, HCV, and HIV among blood donors leads to cost-effectiveness ratios that are far beyond what is usually considered cost-effective. The main reason for this is that with current methods, the risks for virus transmission are very low in Sweden.

Serologic analysis of returned travelers with fever, Sweden.

We studied 1,432 febrile travelers from Sweden who had returned from malaria-endemic areas during March 2005-March 2008. In 383 patients, paired serum samples were blindly analyzed for influenza and 7 other agents. For 21% of 115 patients with fever of unknown origin, serologic analysis showed that influenza was the major cause.