Retrospective investigation of IgM antibodies against Zika virus in serum from febrile patients in Mozambique, 2009-2015.

OBJECTIVE: Zika virus (ZIKV) has emerged as an important health problem worldwide. The aim of this study was to investigate the occurrence, geographical distribution and trend of immunoglobulin M (IgM) antibodies against ZIKV between 2009 and 2015 in Mozambique. RESULTS: The median age of participants was 3 years [interquartile range (IQR): 1.0-6.0 years)] and 56.5% (480/850) of them were male. Of the 850 samples, 42 (4.9%) were positive for IgM antibodies against ZIKV. Positive samples were found in 9 provinces of the country. Frequency of IgM antibodies against ZIKV was slightly higher in patients aged 5-9 years old, and in the north region of the country.

Retrospective investigation of antibodies against chikungunya virus (CHIKV) in serum from febrile patients in Mozambique, 2009-2015: Implications for its prevention and control.

INTRODUCTION: Longitudinal data and trends about chikungunya virus (CHIKV) are critical for its control, however in Mozambique very few studies were conducted over 5 decades, between 1957 and 2013. In this study, we retrospectively investigated the occurrence, geographical distribution and trend of anti-CHIKV antibodies between 2009 and 2015 in Mozambique using serum samples from febrile patients. METHODS: A total of 895 serum samples collected from febrile patients for measles and rubella surveillance between 2009 and 2015 in 127 districts of Mozambique were retrospectively tested for IgM and IgG antibodies against CHIKV using a commercially available ELISA. RESULTS: The median age of patients was 2 years (IQR: 1-5 years) and 44.2% (395/895) of them were female. We found that 54 (6.0%) of samples were positive for anti-IgM chikungunya, and 160 (17.9%) were positive for anti-CHIKV IgG. Antibodies against CHIKV (IgM and IgG) were identified in serum throughout 2009 to 2015. While frequency of IgG antibodies was significantly higher in 2015 as compared to other years, frequency of IgM antibodies was homogeneous between 2009 and 2015. Antibodies against CHIKV were reported in all provinces and in 84 (66.1%) of the districts studied. Frequency of IgM and IgG antibodies was not significantly similar between age groups. CONCLUSION: This is the largest and longest serological screening of antibodies against CHIKV in febrile patients in Mozambique and findings from this study suggest that Mozambicans from all over the country have been silently exposed to CHIKV for several years.

Retrospective investigation of antibodies against chikungunya virus (CHIKV) in serum from febrile patients in Mozambique, 2009-2015: Implications for its prevention and control

Introduction: Longitudinal data and trends about chikungunya virus (CHIKV) are critical for its control, however in Mozambique very few studies were conducted over 5 decades, between 1957 and 2013. In this study, we retrospectively investigated the occurrence, geographical distribution and trend of anti-CHIKV antibodies between 2009 and 2015 in Mozambique using serum samples from febrile patients. Methods: A total of 895 serum samples collected from febrile patients for measles and rubella surveillance between 2009 and 2015 in 127 districts of Mozambique were retrospectively tested for IgM and IgG antibodies against CHIKV using a commercially available ELISA. Results: The median age of patients was 2 years (IQR: 1-5 years) and 44.2% (395/895) of them were female. We found that 54 (6.0%) of samples were positive for anti-IgM chikungunya, and 160 (17.9%) were positive for anti-CHIKV IgG. Antibodies against CHIKV (IgM and IgG) were identified in serum throughout 2009 to 2015. While frequency of IgG antibodies was significantly higher in 2015 as compared to other years, frequency of IgM antibodies was homogeneous between 2009 and 2015. Antibodies against CHIKV were reported in all provinces and in 84 (66.1%) of the districts studied. Frequency of IgM and IgG antibodies was not significantly similar between age groups. Conclusion: This is the largest and longest serological screening of antibodies against CHIKV in febrile patients in Mozambique and findings from this study suggest that Mozambicans from all over the country have been silently exposed to CHIKV for several years.

Evidence for chikungunya and dengue transmission in Quelimane, Mozambique: Results from an investigation of a potential outbreak of chikungunya virus.

BACKGROUND: In January 2016, health authorities from Zambézia province, Mozambique reported the detection of some patients presenting with fever, arthralgia, and a positive result for chikungunya in an IgM-based Rapid Diagnostic Test (RDT). We initiated a study to investigate a potential chikungunya outbreak in the city of Quelimane. METHODS/PRINCIPAL FINDINGS: From February to June 2016, we conducted a cross-sectional study enrolling febrile patients attending five outpatient health units in Quelimane. Serum from each patient was tested for CHIKV and DENV, using IgM and IgG ELISA and qRT-PCR. Patients were also tested for malaria by RDT. Entomological surveys were performed around patients' households, and we calculated the proportion of positive ovitraps and the egg density per trap. A total of 163 patients were recruited, of which 99 (60.7%) were female. The median age was 28 years. IgM and IgG anti-CHIKV antibodies were identified in 17 (10.4%) and 103 (63.2%) patients, respectively. Plaque reduction neutralization assay confirmed the presence of anti-CHIKV antibodies in a subset of 11 tested patients with positive IgG results. IgM anti-DENV antibodies were found in 1 (0.9%) of 104 tested patients. Malaria was diagnosed in 35 (21.5%) patients, 2 of whom were also IgM-positive for CHIKV. Older age and lower education level were independently associated with the prevalence of IgG anti-CHIKV antibodies. Immature forms of Aedes aegypti were collected in 16 (20.3%) of 79 surveyed households. We also found that 25.0% (16/64) of the traps were positive, with an average of 90.8 eggs per pallet. CONCLUSIONS: Our investigation demonstrated that no CHIKV outbreak was ongoing in Quelimane; rather, endemic transmission of the virus has been ongoing. Aedes aegypti mosquitoes are abundant, but dengue cases occurred only sporadically. Further population-based cohort studies are needed to improve our understanding of aspects related to the dynamics of arboviral transmission in Mozambique, as well as in other parts of Sub-Saharan Africa.

Seroepidemiology of leptospirosis among febrile patients in a rapidly growing suburban slum and a flood-vulnerable rural district in Mozambique, 2012-2014: Implications for the management of fever.

OBJECTIVE: Leptospirosis is one of the most widespread zoonoses in the world and is caused by spirochetes of the genus Leptospira. In Mozambique, the disease is largely ignored and its epidemiology is unknown. The objective of this study was to investigate the occurrence of leptospirosis in febrile patients. METHODS: This cross-sectional study was performed between July 2012 and September 2015 among febrile patients. A total of 373 paired serum samples were drawn from febrile patients; 208 were from Caia District Hospital (rural setting) in Sofala Province and 165 were from Polana Caniço General Hospital (suburban setting) in Maputo City. Samples were initially screened using an in-house ELISA for IgM and IgG antibodies. Double positive samples were confirmed using a microagglutination test (MAT). RESULTS: Of the 373 febrile patients, five (1.3%) had acute leptospirosis (MAT ≥400) and 38 (10.2%) had a presumptive infection (IgM-positive/MAT <400). While most of the patients with a presumptive infection lived in the rural setting (84.2%, 32/38), the majority of patients with acute infections (60%, 3/5) and with negative results (60.3%, 199/330) lived in the suburban setting (p=0.000). Contact with rodents was significantly higher in patient with acute leptospirosis (100%, 5/5) than in those with a presumptive infection (39.5%, 15/38) or negative results (41.8%, 138/330) (p=0.031). Four out of the five patients (80%) with acute leptospirosis were treated with antimalarial drugs although malaria results were negative. The prevailing serogroup, according to MAT results, was Australis (40%; 4/10), followed by Icterohaemorrhagiae (30%, 3/10). CONCLUSIONS: This study found that leptospirosis is prevalent among Mozambicans, and most cases are misdiagnosed as malaria.

First serological evidence of Crimean-Congo haemorrhagic fever in febrile patients in Mozambique.

OBJECTIVE: Despite its geographical spread, the epidemiology of Crimean-Congo haemorrhagic fever (CCHF) in Sub-Saharan Africa is incompletely understood and its occurrence in Mozambique is unknown. This study was conducted with the aim of investigating the occurrence of CCHF virus (CCHFV) among febrile patients attending an outpatient appointment clinic at three separate primary health care centres in Mozambique. METHODS: Serum samples were collected from a total of 300 febrile patients aged >5 years who were recruited between March 2015 and March 2016 at three health centres in Mozambique. Each patient was screened for IgG antibodies against CCHFV using an ELISA. RESULTS: Of the 300 patients enrolled, eight had samples that were positive for anti-CCHFV IgG antibodies, yielding a prevalence rate of 2.7%. CONCLUSIONS: This study shows for the first time that humans are exposed to CCHFV in Mozambique. It highlights the need for further work to investigate the broader extent of circulating CCHFV in the country and its clinical implications.

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.

Serological Evidence of Chikungunya Virus among Acute Febrile Patients in Southern Mozambique.

BACKGROUND: In the last two decades, chikungunya virus (CHIKV) has rapidly expanded to several geographical areas, causing frequent outbreaks in sub-Saharan Africa, South East Asia, South America, and Europe. Therefore, the disease remains heavily neglected in Mozambique, and no recent study has been conducted. METHODS: Between January and September 2013, acute febrile patients with no other evident cause of fever and attending a health center in a suburban area of Maputo city, Mozambique, were consecutively invited to participate. Paired acute and convalescent serum samples were requested from each participant. Convalescent samples were initially screened for anti-CHIKV IgG using a commercial indirect immunofluorescence test, and if positive, the corresponding acute sample was screened using the same test. RESULTS: Four hundred patients were enrolled. The median age of study participants was 26 years (IQR: 21-33 years) and 57.5% (224/391) were female. Paired blood samples were obtained from 209 patients, of which 26.4% (55/208) were presented anti-CHIKV IgG antibodies in the convalescent sample. Seroconversion or a four-fold titer rise was confirmed in 9 (4.3%) patients. CONCLUSION: The results of this study strongly suggest that CHIKV is circulating in southern Mozambique. We recommend that CHIKV should be considered in the differential diagnosis of acute febrile illness in Mozambique and that systematic surveillance for CHIKV should be implemented.