Antibodies Against Chikungunya in Northern Mozambique During Dengue Outbreak, 2014.

An outbreak of dengue and high densities of Aedes aegypti were reported in 2014 in northern Mozambique, suggesting an increased risk for other arboviruses such as chikungunya virus (CHIKV) in this region. The aim of this study was to investigate the occurrence of CHIKV during an outbreak of dengue virus (DENV) in Pemba city in northern Mozambique in 2014. Febrile patients (n = 146) seeking medical attention at the Pemba Provincial Hospital between March and April 2014 were enrolled in this study. Blood samples from each participant were tested for chikungunya and DENV RNA, IgM and IgG antibodies using PCR and ELISA, respectively. The median age of the patients was 26 years (interquartile range: 20-34 years), and 52.7% (77/146) were female. We found that 7.0% (8/114) of the patients were positive for CHIKV IgM and 31.5% (46/146) presented with CHIKV IgG antibodies. DENV IgM and IgG antibodies were detected in 38.3% (46/120) and 28.2% (33/117) of the patients, respectively. This study is the first investigation regarding the occurrence of CHIKV in the north of Mozambique over the last 60 years and our data suggest that Mozambicans had been silently exposed to the virus in this part of the country, indicating that not only DENV but also CHIKV is an arbovirus to consider in febrile patients seeking medical attention in northern Mozambique.

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.

Severe Chikungunya infection in Northern Mozambique: a case report.

BACKGROUND: Although Chikungunya virus has rapidly expanded to several countries in sub-Saharan Africa, little attention has been paid to its control and management. Until recently, Chikungunya has been regarded as a benign and self-limiting disease. In this report we describe the first case of severe Chikungunya disease in an adult patient in Pemba, Mozambique. CASE PRESENTATION: A previously healthy 40 year old male of Makonde ethnicity with no known past medical history and resident in Pemba for the past 11 years presented with a severe febrile illness. Despite administration of broad spectrum intravenous antibiotics the patient rapidly deteriorated and became comatose while developing anaemia, thrombocytopenia and later, melaena. Laboratory testing revealed IgM antibodies against Chikungunya virus. Malaria tests were consistently negative. CONCLUSIONS: This report suggests that Chikungunya might cause unsuspected severe disease in febrile patients in Mozambique and provides insights for the improvement of national protocols for management of febrile patients in Mozambique. We recommend that clinicians should consider Chikungunya in the differential diagnosis of febrile illness in locations where Aedes aegypti mosquitos are abundant.

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.

Discovery of Novel Viruses in Mosquitoes from the Zambezi Valley of Mozambique.

Mosquitoes carry a wide variety of viruses that can cause vector-borne infectious diseases and affect both human and veterinary public health. Although Mozambique can be considered a hot spot for emerging infectious diseases due to factors such as a rich vector population and a close vector/human/wildlife interface, the viral flora in mosquitoes have not previously been investigated. In this study, viral metagenomics was employed to analyze the viral communities in Culex and Mansonia mosquitoes in the Zambezia province of Mozambique. Among the 1.7 and 2.6 million sequences produced from the Culex and Mansonia samples, respectively, 3269 and 983 reads were classified as viral sequences. Viruses belonging to the Flaviviridae, Rhabdoviridae and Iflaviridae families were detected, and different unclassified single- and double-stranded RNA viruses were also identified. A near complete genome of a flavivirus, tentatively named Cuacua virus, was obtained from the Mansonia mosquitoes. Phylogenetic analysis of this flavivirus, using the NS5 amino acid sequence, showed that it grouped with 'insect-specific' viruses and was most closely related to Nakiwogo virus previously identified in Uganda. Both mosquito genera had viral sequences related to Rhabdoviruses, and these were most closely related to Culex tritaeniorhynchus rhabdovirus (CTRV). The results from this study suggest that several viruses specific for insects belonging to, for example, the Flaviviridae and Rhabdoviridae families, as well as a number of unclassified RNA viruses, are present in mosquitoes in Mozambique.

Arabidopsis thaliana plants expressing Rift Valley fever virus antigens: Mice exhibit systemic immune responses as the result of oral administration of the transgenic plants.

The zoonotic Rift Valley fever virus affects livestock and humans in Africa and on the Arabian Peninsula. The economic impact of this pathogen due to livestock losses, as well as its relevance to public health, underscores the importance of developing effective and easily distributed vaccines. Vaccines that can be delivered orally are of particular interest. Here, we report the expression in transformed plants (Arabidopsis thaliana) of Rift Valley fever virus antigens. The antigens used in this study were the N protein and a deletion mutant of the Gn glycoprotein. Transformed lines were analysed for specific mRNA and protein content by RT-PCR and Western blotting, respectively. Furthermore, the plant-expressed antigens were evaluated for their immunogenicity in mice fed the transgenic plants. After oral intake of fresh transgenic plant material, a proportion of the mice elicited specific IgG antibody responses, as compared to the control animals that were fed wild-type plants and of which none sero-converted. Thus, we show that transgenic plants can be readily used to express and produce Rift Valley Fever virus proteins, and that the plants are immunogenic when given orally to mice. These are promising findings and provide a basis for further studies on edible plant vaccines against the Rift Valley fever virus.

Acute Uncomplicated Febrile Illness in Children Aged 2-59 months in Zanzibar - Aetiologies, Antibiotic Treatment and Outcome.

BACKGROUND: Despite the fact that a large proportion of children with fever in Africa present at primary health care facilities, few studies have been designed to specifically study the causes of uncomplicated childhood febrile illness at this level of care, especially in areas like Zanzibar that has recently undergone a dramatic change from high to low malaria transmission. METHODS: We prospectively studied the aetiology of febrile illness in 677 children aged 2-59 months with acute uncomplicated fever managed by IMCI (Integrated Management of Childhood Illness) guidelines in Zanzibar, using point-of-care tests, urine culture, blood-PCR, chest X-ray (CXR) of IMCI-pneumonia classified patients, and multiple quantitative (q)PCR investigations of nasopharyngeal (NPH) (all patients) and rectal (GE) swabs (diarrhoea patients). For comparison, we also performed NPH and GE qPCR analyses in 167 healthy community controls. Final fever diagnoses were retrospectively established based on all clinical and laboratory data. Clinical outcome was assessed during a 14-day follow-up. The utility of IMCI for identifying infections presumed to require antibiotics was evaluated. FINDINGS: NPH-qPCR and GE-qPCR detected ≥1 pathogen in 657/672 (98%) and 153/164 (93%) of patients and 158/166 (95%) and 144/165 (87%) of controls, respectively. Overall, 57% (387/677) had IMCI-pneumonia, but only 12% (42/342) had CXR-confirmed pneumonia. Two patients were positive for Plasmodium falciparum. Respiratory syncytial virus (24.5%), influenza A/B (22.3%), rhinovirus (10.5%) and group-A streptococci (6.4%), CXR-confirmed pneumonia (6.2%), Shigella (4.3%) were the most common viral and bacterial fever diagnoses, respectively. Blood-PCR conducted in a sub-group of patients (n = 83) without defined fever diagnosis was negative for rickettsiae, chikungunya, dengue, Rift Valley fever and West Nile viruses. Antibiotics were prescribed to 500 (74%) patients, but only 152 (22%) had an infection retrospectively considered to require antibiotics. Clinical outcome was generally good. However, two children died. Only 68 (11%) patients remained febrile on day 3 and three of them had verified fever on day 14. An additional 29 (4.5%) children had fever relapse on day 14. Regression analysis determined C-reactive Protein (CRP) as the only independent variable significantly associated with CXR-confirmed pneumonia. CONCLUSIONS: This is the first study on uncomplicated febrile illness in African children that both applied a comprehensive laboratory panel and a healthy control group. A majority of patients had viral respiratory tract infection. Pathogens were frequently detected by qPCR also in asymptomatic children, demonstrating the importance of incorporating controls in fever aetiology studies. The precision of IMCI for identifying infections requiring antibiotics was low.

Multiplex nucleic acid suspension bead arrays for detection and subtyping of filoviruses.

Here we describe multiplex suspension bead array systems that allow fast and reliable detection of reverse transcriptase (RT) PCR amplified filovirus genomes and also enable subtyping of Ebola virus species and Marburg virus strains. These systems have an analytical sensitivity equivalent to that of RT-PCR.

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.

Detection of antibodies against H5 and H7 strains in birds: evaluation of influenza pseudovirus particle neutralization tests.

INTRODUCTION: Avian influenza viruses circulate in bird populations, and it is important to maintain and uphold our knowledge of the viral strains that are currently of interest in this context. Here, we describe the use of hemagglutinin-pseudotype retroviruses based on highly pathogenic influenza viruses for the screening of avian sera for influenza A antibodies. Our aim was also to determine whether the pseudovirus neutralization tests that we assessed were sensitive and simple to use compared to the traditional methods, including hemagglutination inhibition assays and microneutralization tests. MATERIAL AND METHODS: H5 and H7 pseudovirus neutralization tests were evaluated by using serum from infected rabbits. Subsequently, the assays were further investigated using a panel of serum samples from avian species. The panel contained samples that were seropositive for five different hemagglutinin subtypes as well as influenza A seronegative samples. RESULTS AND DISCUSSION: The results suggest that the pseudovirus neutralization test is an alternative to hemagglutination inhibition assays, as we observed comparable titers to those of both standard microneutralizations assays as well as hemagglutinin inhibition assays. When evaluated by a panel of avian sera, the method also showed its capability to recognize antibodies directed toward low-pathogenic H5 and H7. Hence, we conclude that it is possible to use pseudoviruses based on highly pathogenic avian influenza viruses to screen avian sera for antibodies directed against influenza A subtypes H5 and H7.

Antibodies against Rift Valley Fever Virus in Cattle, Mozambique

During the past 2 decades, several countries in Africa and the Arabian Peninsula, to which Rift Valley fever virus (RVFV) is endemic, have reported outbreaks of Rift Valley fever in humans and livestock. The first evidence of RVFV in Mozambique was documented as early as the 1960s (1). Endemicity was subsequently confirmed in the 1980s by a prevalence study that identified virusspecific antibodies in 2% of pregnant women (2) and in the 1990s by serosurveillance in Zambezia Province, which showed that cattle had been infected with RVFV.

Effect of acute Plasmodium falciparum malaria on reactivation and shedding of the eight human herpes viruses.

Human herpes viruses (HHVs) are widely distributed pathogens. In immuno-competent individuals their clinical outcomes are generally benign but in immuno-compromised hosts, primary infection or extensive viral reactivation can lead to critical diseases. Plasmodium falciparum malaria profoundly affects the host immune system. In this retrospective study, we evaluated the direct effect of acute P. falciparum infection on reactivation and shedding of all known human herpes viruses (HSV-1, HSV-2, VZV, EBV, CMV, HHV-6, HHV-7, HHV-8). We monitored their presence by real time PCR in plasma and saliva of Ugandan children with malaria at the day of admission to the hospital (day-0) and 14 days later (after treatment), or in children with mild infections unrelated to malaria. For each child screened in this study, at least one type of HHV was detected in the saliva. HHV-7 and HHV-6 were detected in more than 70% of the samples and CMV in approximately half. HSV-1, HSV-2, VZV and HHV-8 were detected at lower frequency. During salivary shedding the highest mean viral load was observed for HSV-1 followed by EBV, HHV-7, HHV-6, CMV and HHV-8. After anti-malarial treatment the salivary HSV-1 levels were profoundly diminished or totally cleared. Similarly, four children with malaria had high levels of circulating EBV at day-0, levels that were cleared after anti-malarial treatment confirming the association between P. falciparum infection and EBV reactivation. This study shows that acute P. falciparum infection can contribute to EBV reactivation in the blood and HSV-1 reactivation in the oral cavity. Taken together our results call for further studies investigating the potential clinical implications of HHVs reactivation in children suffering from malaria.

Systematic screening of BK virus by real-time PCR prevents BK virus associated nephropathy in renal transplant recipients.

BK virus associated nephropathy occurs in approximately 5% of renal transplant recipients. Quantitation of BKV DNA in serum/plasma early in the course of disease has been suggested to be an important diagnostic tool for polymavirus-associated nephropathy (PVAN). The aim of this study was to develop a BKV real-time PCR (qPCR), which could be included in a diagnostic qPCR platform. Additionally, the significance of the assay as a surrogate marker for PVAN was investigated. Quantitation of BKV DNA by qPCR was carried out on 234 serum samples from a retrospective study including 31 renal transplant recipients monitored for at least 6 months post-transplantation. BKV viremia was detected in 9 out of 31 patients. Four patients had a viral load of >10,000 copies/ml at least on one occasion. In two of these patients, PVAN was diagnosed clinically during the study period. In retrospect, these patients were shown to be BKV positive before the clinical diagnosis of PVAN was made. Another two patients had a permanent graft dysfunction, but were never clinically diagnosed with PVAN. None of the remaining five patients with BKV DNA (<10,000 copies/ml) had renal impairment. Based on these results, an algorithm was introduced at the study center in 2006 and to date, August 2011, no cases of PVAN with loss of graft have been observed. The concept of including different PCR protocols in a common qPCR platform allows laboratories with small sample numbers to perform regularly a variety of assays at a reasonable cost.

Surveillance for West Nile virus in wild birds from northern Europe.

A total of 1935 migratory birds from 104 different species were captured in southeastern Sweden in 2005-2006 and tested for antibodies against West Nile virus (WNV). Overall, 46 birds (2.4%; binomial confidence limits, 1.8-3.2) were positive by blocking-ELISA, but only 2 (0.10%; binomial confidence limits, 0.0-0.4) had antibodies detectable by both blocking-ELISA and WNV neutralization test. ELISA-positive birds included long- and short-distance migrants likely exposed to WNV while wintering in or migrating through areas enzootic for WNV. Exposure to a cross-reactive Flavivirus was suspected for short-distance migrants of the Turdidae family, but no cross-neutralization with tick-borne encephalitis and Usutu viruses was observed.

Anchored pan dengue RT-PCR and fast sanger sequencing for detection of dengue RNA in human serum.

A large number of human infections are caused by different dengue virus strains, mainly in the tropical and subtropical parts of the world, but also outside the endemic regions. RT-PCR methods are used widely for detection of dengue virus RNA in acute-phase serum samples; however, new sequence variation can inhibit these methods. An assay was developed integrating an anchored Pan Dengue RT-PCR with a new Fast Sanger sequencing protocol. For broad detection and identification of dengue virus RNA, including new strains of all serotypes, the conserved 3' genome end was targeted for highly specific cDNA synthesis. A combination of degenerated primers was used for second strand synthesis, followed by tag primed amplification. The mixture of generated amplicons was identified directly by the Fast Sanger sequencing from the anchored 3' genome end. Evaluating the assay on human serum RNA spiked with viral RNA representing the four dengue serotypes demonstrated a detection limit of 44-124 copies viral RNA per reaction for a two-step format of the anchored Pan Dengue RT-PCR and 100-500 copies for a one-step protocol, respectively. The different serotypes were clearly identified from the generated sequences. Further, the 5-hr procedure was evaluated and compared to standard real-time RT-PCR protocols on acute-phase serum samples from patients with confirmed dengue infections. This assay demonstrates a strategy for virus detection, which combines nucleic acid amplification adapted for dengue virus RNA with direct and rapid sequencing. It provides a tolerance for new sequence variation and the strategy should be applicable for other RNA viruses.

Primary infection with the Epstein-Barr virus and risk of multiple sclerosis.

To determine whether multiple sclerosis (MS) risk increases following primary infection with the Epstein-Barr virus (EBV), we conducted a nested case-control study including 305 individuals who developed MS and 610 matched controls selected among the >8 million active-duty military personnel whose serum has been stored in the Department of Defense Serum Repository. Time of EBV infection was determined by measuring antibody titers in serial serum samples collected before MS onset among cases, and on matched dates among controls. Ten (3.3%) cases and 32 (5.2%) controls were initially EBV negative. All of the 10 EBV-negative cases became EBV positive before MS onset; in contrast, only 35.7% (n = 10) of the 28 controls with follow-up samples seroconverted (exact p value = 0.0008). We conclude that MS risk is extremely low among individuals not infected with EBV, but it increases sharply in the same individuals following EBV infection.

Monitoring of herpes simplex virus DNA types 1 and 2 viral load in cerebrospinal fluid by real-time PCR in patients with herpes simplex encephalitis.

A quantitative polymerase chain reaction (PCR) assay was evaluated retrospectively on 92 cerebrospinal fluid (CSF) samples from 29 patients with herpes simplex virus (HSV) encephalitis with the aim to study if the concentration of HSV genomes can be used as a prognostic marker and for monitoring of antiviral therapy. The results were compared to those obtained previously by nested PCR, and the numbers of HSV genomes/ml were evaluated in correlation to patient outcome and treatment. The aims were to compare the sensitivity of a conventional nested PCR to a quantitative PCR, to investigate the range of HSV genome concentration in initial samples and to evaluate possible relationships between the HSV DNA concentrations in CSF, neopterin levels, and outcome of disease. The 29 initial samples contained between 2 x 10(2) and 42 x 10(6) HSV genomes/ml. There was no apparent correlation between the amount of HSV DNA in the initial samples and income status, initial neopterin levels, or prognosis. The number of HSV genomes/ml declined after treatment in all patients, but HSV DNA was still detectable after day 20 in 3 out of 16 patients. A long duration of genome detectability was found to correlate with poor outcome. There was no difference in sensitivity between the nested PCR and the quantitative PCR. While the quantitative PCR is more rational than a nested PCR, the quantitation of HSV genomes does not seem very useful as a prognostic marker in HSV encephalitis.