Emerging Zoonotic Diseases among Pastoral Communities of Caia and Búzi Districts, Sofala, Mozambique: Evidence of Antibodies against Brucella, Leptospira, Rickettsia, and Crimean-Congo Hemorrhagic Fever Virus

Emerging zoonotic diseases are an increasing threat to public health. There is little data on the seroprevalence of zoonotic diseases among pastoralists in the country. We aim to carry out a cross-sectional study on the prevalence of major zoonotic diseases among pastoral communities in the Caia and Búzi districts. Methods: Between January and December 2018, a questionnaire was used to solicit socio-demographic data from consenting pastoralists with the collection of blood samples in the Caia and Búzi districts of the Sofala province. All samples were tested using ELISA commercial reagents for the detection of IgM antibodies against Brucella and Leptospira. Likewise, IgM and IgG antibodies against Rickettsia and CCHFV were determined using ELISA kits. Results: A total of 218 samples were tested, of which 43.5% (95/218) were from the district of Caia and 56.4% (123/218) from the Búzi district. Results from both districts showed that the seroprevalence of IgM antibodies against Brucella and Leptospira was 2.7% (6/218) and 30.3% (67/218), respectively. Positivity rates for IgM and IgG anti-Rickettsia and CCHFV were 8.7% (19/218), 2.7% (6/218), 4.1% (9/218), and 0.9% (2/218), respectively. Conclusions: Results from our study showed evidence of antibodies due to exposure to Brucella, Leptospira, Rickettsia, and CCHFV with antibodies against Leptospira and Rickettsia being the most prevalent. Hence, laboratory diagnosis of zoonotic diseases is essential in the early detection of outbreaks, the identification of silent transmission, and the etiology of non-febrile illness in a pastoral community. There is a need to develop public health interventions that will reduce the risk of transmission.

Emerging Zoonotic Diseases among Pastoral Communities of Caia and Búzi Districts, Sofala, Mozambique: Evidence of Antibodies against Brucella, Leptospira, Rickettsia, and Crimean-Congo Hemorrhagic Fever Virus.

BACKGROUND: Emerging zoonotic diseases are an increasing threat to public health. There is little data on the seroprevalence of zoonotic diseases among pastoralists in the country. We aim to carry out a cross-sectional study on the prevalence of major zoonotic diseases among pastoral communities in the Caia and Búzi districts. METHODS: Between January and December 2018, a questionnaire was used to solicit socio-demographic data from consenting pastoralists with the collection of blood samples in the Caia and Búzi districts of the Sofala province. All samples were tested using ELISA commercial reagents for the detection of IgM antibodies against Brucella and Leptospira. Likewise, IgM and IgG antibodies against Rickettsia and CCHFV were determined using ELISA kits. RESULTS: A total of 218 samples were tested, of which 43.5% (95/218) were from the district of Caia and 56.4% (123/218) from the Búzi district. Results from both districts showed that the seroprevalence of IgM antibodies against Brucella and Leptospira was 2.7% (6/218) and 30.3% (67/218), respectively. Positivity rates for IgM and IgG anti-Rickettsia and CCHFV were 8.7% (19/218), 2.7% (6/218), 4.1% (9/218), and 0.9% (2/218), respectively. CONCLUSIONS: Results from our study showed evidence of antibodies due to exposure to Brucella, Leptospira, Rickettsia, and CCHFV with antibodies against Leptospira and Rickettsia being the most prevalent. Hence, laboratory diagnosis of zoonotic diseases is essential in the early detection of outbreaks, the identification of silent transmission, and the etiology of non-febrile illness in a pastoral community. There is a need to develop public health interventions that will reduce the risk of transmission.

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.

Seroepidemiology of Chikungunya Virus Among Febrile Patients in Eight Health Facilities in Central and Northern Mozambique, 2015-2016.

BACKGROUND: The burden and spread of chikungunya virus (CHIKV) are rapidly increasing worldwide, but the epidemiology in Mozambique is barely known. The aim of this study was to determine the seroepidemiology of CHIKV in central and northern Mozambique. METHODS: A cross-sectional study was conducted between March 2015 and May 2016 in eight health facilities situated in central and northern Mozambique to recruit 392 patients with undifferentiated febrile illness from outpatient clinics. Serum samples from each participant were screened using commercially available enzyme-linked immunosorbent assay for detection of anti-CHIK IgM and IgG antibodies. A subset of study samples (n = 37) was further tested by the plaque reduction neutralization assay (PRNT). RESULTS: The median age of participants was 23 years (IQR: 7-34), and 45.7% were female. The frequency of participants with seropositivity for IgM and IgG anti-CHIKV antibodies was 1.5% (6/392) and 28.6% (112/392), respectively. Patients with seropositivity for IgM anti-CHIKV were significantly younger. Frequency of patients with seropositivity for IgG anti-CHIKV increased with age. Frequency of patients with seropositivity for IgM anti-CHIKV was higher in Tete province, but most patients with seropositivity for IgG anti-CHIKV infection were from Cabo Delgado and Sofala provinces. CONCLUSIONS: Our data demonstrate serological evidence of CHIKV in central and northern Mozambique, expanding the limited evidence of the virus in the country. We recommend that CHIKV should be considered in the differential diagnosis of febrile illness throughout the country.

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.

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.