[Show abstract][Hide abstract] ABSTRACT: In Senegal, with the variable routine vaccination coverage, the risk for illness and death from measles still exists as evidenced by the measles epidemic episode in 2009. Since 2002 a laboratory-based surveillance system of measles was established by the Ministry of Health and the Institut Pasteur de Dakar. The present study analysed the data collected over the 10 years inclusive between 2004-2013 in order to define a measles epidemiological profile in Senegal, and we carried out a phylogenetic analysis of measles virus circulating in Senegal over the period 2009-2012.
A total number of 4580 samples were collected from suspected cases, with the most cases between 2008 and 2010 (2219/4580; 48.4%). The majority of suspected cases are found in children from 4-6 years old (29%). 981 (21.4%) were measles laboratory-confirmed by IgM ELISA. The measles confirmation rate per year is very high during 2009-2010 periods (48.5% for each year). Regarding age groups, the highest measles IgM-positivity rate occurred among persons aged over 15 years with 39.4% (115/292) followed by 2-3 years old age group with 30.4% (323/1062) and 30% (148/494) in children under one year old group. The majority of suspected cases were collected between February and June and paradoxically confirmed cases rates increased from July (77/270; 28.6%) and reached a peak in November with 60% (93/155). Phylogenetic analysis showed that all the 29 sequences from strains that circulated in Senegal between 2009 and 2012 belong to the B3 genotype and they are clustered in B3.1 (2011-2012) and B3.3 (2009-2011) sub-genotypes according to a temporal parameter.
Improvements in the measles surveillance in Senegal are required and the introduction of oral fluid and FTA cards as an alternative to transportation of sera should be investigated to improve surveillance. The introduction of a national vaccine database including number of doses of measles-containing vaccine will greatly improve efforts to interrupt and ultimately eliminate measles virus transmission in Senegal.
PLoS ONE 05/2015; 10(5):e0121704. DOI:10.1371/journal.pone.0121704 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
Data on influenza in tropical and resource-limited countries are scarce. In this study we present results from 14 years of influenza surveillance in Senegal, one of the few tropical countries in Africa from which longitudinal data are available.
From 1996 to 2009, we collected respiratory specimens from outpatients presenting with influenza-like illness at 13 facilities in order to investigate the epidemiology of seasonal influenza and the characteristics of the circulating influenza viruses. Specimens were tested for influenza using viral isolation and/or reverse-transcription polymerase chain reaction (RT-PCR).
From 1996 to 2009, specimens were obtained from 9176 patients; 1233 (13%) were influenza-positive by virus isolation and/or RT-PCR. Among positive samples, 958 (77%) were influenza A, 268 (22%) influenza B, and 7 (1%) influenza type C; of influenza A viruses, 619 (65%) were A(H3) and 339 (35%) A(H1), of which 13 (1%) were identified as H1N2. The proportion positive was similar for children <15 years, young adults 16-35 years, and adults 36-55 years (15%), but lower for persons >55 years (9%). Although influenza A(H1), A(H3), and B all circulated during most years, influenza A(H3N2) predominated during 9 of the 14 years. Influenza activity consistently peaked during the rainy season (July-September). Phylogenetic analysis showed that viruses circulating in Senegal were similar to contemporary viruses circulating elsewhere in the world.
Our data confirm that influenza is prevalent in Senegal, occurs in seasonal epidemics, and contributes to the burden of respiratory diseases in all age groups.
The Journal of Infectious Diseases 12/2012; 206 Suppl 1(suppl 1):S129-35. DOI:10.1093/infdis/jis576 · 6.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Acute respiratory infection is one of the leading causes of child morbidity, especially in developing countries. Viruses are recognized as the predominant causative agents of acute respiratory infections. In Senegal, few data concerning the causes of respiratory infections are available, and those known relate mainly to classical influenza infections. Clinical and virological surveillance of acute respiratory infections was carried out in a rural community in children less than 5 years old. A standardized questionnaire was used and a nasopharyngeal swab sample was collected from each patient. These samples were tested for the detection of 20 respiratory viruses by multiplex RT-PCR or by viral culture. A total of 82 acute respiratory episodes were included, and 48 (58.5%) were found to be positive, with a total of 55 viral detections; several samples were positive for two (n = 5) or 3 (n = 1) viruses. Ten different viruses were identified: influenza viruses A, B, and C (n = 25), human respiratory syncytial virus type A (n = 13), rhinoviruses (n = 8), human coronaviruses type 229E and NL63 (n = 6), parainfluenza viruses 3 and 4 (n = 2), and bocavirus (n = 1). These results provide evidence on the importance and the diversity of viruses as causative agents of acute respiratory infections in children living in a rural community in Senegal. The establishment of sentinel surveillance sites could help estimate the burden of acute respiratory infection in the pediatric population and should help prepare the health care systems to identify and respond to new viral respiratory emergencies.
Journal of Medical Virology 05/2010; 82(5):866-72. DOI:10.1002/jmv.21665 · 2.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In October 2003, 9 human cases of hemorrhagic fever were reported in 3 provinces of Mauritania, West Africa. Test results showed acute Rift Valley fever virus (RVFV) infection, and a field investigation found recent circulation of RVFV with a prevalence rate of 25.5% (25/98) and 4 deaths among the 25 laboratory-confirmed case-patients. Immunoglobulin M against RVFV was found in 46% (25/54) of domestic animals. RVFV was also isolated from the mosquito species Culex poicilipes. Genetic comparison of virion segments indicated little variation among the strains isolated. However, phylogenetic studies clearly demonstrated that these strains belonged to the East-Central African lineage for all segments. To our knowledge, this is the first time viruses of this lineage have been observed in an outbreak in West Africa. Whether these strains were introduced or are endemic in West Africa remains to be determined.
[Show abstract][Hide abstract] ABSTRACT: In 1998, circulation of the Rift Valley Fever (RVF) virus was revealed in Diawara by detection of IgM antibodies in sheep and isolation of the virus from mosquitoes caught outside a village. A seroprevalence study was carried out. Finger-prick blood samples, individual and collective details were obtained. One thousand five hundred twenty people (6 months - 83 years) were included. Overall prevalence in this group was approximately 5.2%. The prevalence in infants (6 months - 2 years) was 8.5%. Age, gender, contact with a pond, presence of sheep, and abortion among sheep, and individual or collective travel history were not statistically associated with prevalence. Prevalence increased significantly when the distance to a small ravine, located in the middle of the village, decreased. The results suggest a low, recent, not endemic circulation of the virus. Culex quinquefasciatus was captured near the ravine. This mosquito, similar to Culex pipiens, can play a similar role in human-to-human transmission of the RVF virus.
The Southeast Asian journal of tropical medicine and public health 12/2005; 36(6):1487-95. · 0.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Between May and October 2000, the Regional Health Office of Kolda Region in the south of Senegal, West Africa, reported an epidemic of an unknown illness characterized by thoracic pain, dyspnea and edemas of limb and face. The epidemic covered a radius of approximately 40 km (24 miles) between the districts of Kolda and Sedhiou in Kolda Region. Cases were mostly men whose age ranged between 12 and 60 years old. Investigation revealed that they had been exposed to pesticides distributed by the government to groundnut farmers. The signs and symptoms suggested intoxication with carbamates, carbofurans, and possibly thiram, contained in the pesticides distributed with the groundnut seeds. Government distribution created an excessive use of pesticides in the farms, and consequently an overexposure of the subjects who handled the seeders, especially young males but also a small proportion of women who worked in the groundnut fields. Many of these subjects, not accustomed to handle pesticides, came to overestimate the quantity of product to fill the seeder. It should be noted that the policy of distribution of pesticides in Senegal, which presents risk of poisoning, was not systematically accompanied by sufficient information on the danger of the products and of certain precautions that should be taken during their use.
Journal of Exposure Analysis and Environmental Epidemiology 10/2002; 12(5):381-8. DOI:10.1038/sj.jea.7500239 · 2.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A Rift Valley fever outbreak occurred in Mauritania in 1998. Seroepidemiologic and virologic investigation showed active circulation of the Rift Valley fever virus, with 13 strains isolated, and 16% (range 1.5%-38%) immunoglobulin (Ig) M-positivity in sera from 90 humans and 343 animals (sheep, goats, camels, cattle, and donkeys). One human case was fatal.
[Show abstract][Hide abstract] ABSTRACT: An influenza survey was conducted in seven sentinel sites in Dakar, Senegal from June 1996 to December 1998. Throat or nasal swab cultures were randomly collected from 804 patients suffering from influenza-like symptoms. Influenza viruses were isolated at a similar proportion in adults and in children (P = 0.29). Strains of influenza B viruses were isolated from sporadic cases in 1997, whereas type A virus was associated with an isolated peak. Proportions of influenza virus isolation varied from 17.5% to 40.0% between 1996 and 1998 during the peak period (July/September) of acute respiratory infection in Dakar. Rainfall, humidity, and temperatures rose during the same period. Influenza in Dakar seems to be an-all-age groups respiratory infection characterized by high transmission during the hot and rainy season. The antigenic similarity of the A(H3N2) and B viruses to those circulating elsewhere in the world at the same time was confirmed. However, the A(H1N1) strains were found to be more closely related to an Asiatic strain which had not been isolated outside Asia previously. Consequently, the strain close to the A(H1N1)/Wuhan/371/95 strain isolated in Dakar was included in the composition of the 1998/1999 influenza vaccine. This reinforces the importance of setting up a national influenza control strategy in tropical regions.
The American journal of tropical medicine and hygiene 06/2000; 62(5):639-43. · 2.70 Impact Factor