Evaluation of the Kenya Livestock and Wildlife Syndromic Surveillance System for Rift Valley Fever, Narok County, Kenya, 2018-2019

Abstract Background Rift Valley Fever (RVF) outbreaks in livestock have had a detrimental impact on livestock trade, animal breeding, and productivity. Routine evaluation and data analysis of surveillance systems ensure that health events are efficiently and effectively monitored. This study evaluated Kenya Livestock and Wildlife Surveillance System (KLWSS) and characterized RVF cases reported for Narok County. Methods We evaluated KLWSS from January 2018 to December 2019 using CDC guidelines for evaluating surveillance systems. Attributes of simplicity, flexibility, data quality, acceptability, representativeness, timeliness, stability, sensitivity, and predictive value positive were examined. A retrospective review of RVF surveillance data for Narok County was performed. Demographic and clinical variables were assessed. Data were cleaned in Ms. Excel and descriptive analysis was done using Epi Info 7. Categorical variables were summarized using frequencies and proportions while continuous variables were summarized using measures of central tendency and dispersion. Study authorization was granted by the Directorate of Veterinary Services. Results System was simple in structure and operation, accommodated upgrading of its application, data quality performance was 69.8%, stakeholder’s participation rate was 80% with 842 reports coming from six sub-counties and 30 wards. The median time between event occurrence and event reporting was two days (range one to six days). The system had been operational since 2018 with no reports of any unscheduled outages and downtimes. Suspected cases of RVF reported were 11% (95/842) of the reported cases. The livestock species affected were cattle 56% (53/95) and Sheep 44% (42/95). About 96% (91/95) of the suspected cases were in mixed livestock production systems. The common syndrome was abortions 74% (95/129) with Loita ward recording 97% (92/95) suspected RVF cases. All suspected cases were reported in March 2018. Conclusions The KLWSS system was found to be stable but with below-par performance in data quality. Improvement in data quality is required to ensure that the surveillance system is efficient and effective.

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Detection of Rift Valley Fever Virus Lineage H from South Africa through Syndromic Sentinel Surveillance Network in Senegal

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab655 ◽

2021 ◽

Author(s):

Ndeye Sakha Bob ◽

Mamadou Aliou Barry ◽

Moussa Moise Diagne ◽

Martin Faye ◽

Marie Henriette Dior Ndione ◽

...

Keyword(s):

South Africa ◽

Rift Valley ◽

Surveillance System ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Surveillance Network ◽

Valley Fever

Abstract Background Rift Valley fever virus (RVFV) is an arbovirus that causes epizootics and epidemics among livestock population and humans. Our surveillance system has revealed multiple emergences and re-emergences of RVFV in West Africa over the last decade. Methods In Senegal a sentinel syndromic surveillance network (4S) has been implemented since 2011. Samples from human suspected arbovirus infection in 4S sentinel sites were sent to Institut Pasteur de Dakar (IPD) where arbovirus diagnosis by enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription polymerase chain reaction (RT-PCR), and virus isolation were performed. Overall, IPD has received a total of 1,149 samples from arboviral suspected patients through the 4S network from January to December 2020. These samples were screened for seven arboviruses including RVFV. Whole genome sequencing of positive RVFV samples by RT-PCR were performed using Illumina Miseq platform followed by genome assembly. Phylogenetic analysis were performed using MEGA X. Results Out of the 1,149 arbovirus suspected cases, four RVFV positive samples were detected with RT-PCR while five RVFV positive samples were detected by ELISA. Complete genome sequences were obtained for three strains among the four positive samples by RT-PCR. Phylogenetic analyses indicated an emergence of a virus first described in South Africa during a major outbreak. Conclusion Strong surveillance system allowed the detection of RVFV outbreak in Senegal in 2020. The obtained genomes clustered with strains from South Africa belonging to lineage H. This calls for an implementation of a strong surveillance system in wild animals, humans, and livestock simultaneously in all African Countrries.

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Seropositivity and associated intrinsic and extrinsic factors for Rift Valley fever virus occurrence in pastoral herds of Nigeria: A cross sectional survey

10.21203/rs.2.15982/v2 ◽

2020 ◽

Author(s):

Nma Bida Alhaji ◽

Jibrin Aminu ◽

Mohammed Kabir Lawan ◽

Olutayo Olajide Babalobi ◽

Ibrahim Ghali-Mohammed ◽

...

Keyword(s):

Public Health ◽

Rift Valley ◽

Rift Valley Fever ◽

Ecological Factors ◽

Categorical Variables ◽

Cross Sectional ◽

Valley Fever ◽

North Central ◽

Pastoral Cattle ◽

Cattle Herds

Abstract Background: Rift Valley fever (RVF) is a vector-borne emerging zoonotic disease of animals and humans, characterized by major socioeconomic losses to livestock farmers, with potential global public health threat. The study determined RVFV seroprevalence in cattle, as well as assessed pastoralists’ existing knowledge about the diseases, and factors that influence RVFV occurrence in pastoral cattle herds of Nigeria. Methods: A cross-sectional study was conducted in pastoral herds of North-central Nigeria from 2017 to 2018. Data collections were carried out using serology and questionnaire tools. Descriptive statistics, using frequencies and proportions, were used to analyze data obtained from the survey. Categorical variables were presented as proportions and their associations determined by Chi-square tests. Associations of risk factors were analyzed by univariable and multivariable logistic regressions analyses at 95% confidence level. Results: The overall IgM seropositivity of RVFV in pastoral cattle herds of North-central Nigeria was 5.6%. This was higher in nomadic cattle (7.4%) than agro-pastoral animals (3.8%). All animal demographic characteristics of age, sex and breeds were not significantly (p>0.05) associated with RVFV occurrence in pastoral herds. All the 403 pastoralists selected participated in the study, with the majorities of respondents being male, married and having formal education. Majority of the pastoralists had low knowledge levels about zoonotic RVFV infection. However, all identified socio-ecological factors significantly (p<0.05) influenced RVFV occurrence in pastoral cattle herds. Mosquitoes availability in cattle herds environment (OR=7.81; 95% CI: 4.85, 12.37), presence of rivers and streams at grazing fields (OR=10.80; 95% CI: 6.77, 17.34), high rainfall (OR=4.30; 95% CI: 2.74, 6.59), irrigated rice fields (OR=5.14; 95% CI: 3.21, 7.79) , bushy vegetation (OR=6.11; 95% CI: 3.96, 9.43), animal movement (OR=2.2; 95% CI: 1.45, 3.25), and seasons (OR=2.34; 95% CI: 1.55, 3.51) were more likely to influence RVFV occurrence in pastoral cattle herds. Conclusions: The results of this study illustrated recent circulation of RVFV in pastoral cattle herds of Nigeria and needs urgent interventions. Low levels of knowledge about RVF were also highlighted amongst surveyed pastoralists and identified socio-ecological factors significantly influenced RVFV occurrence in herds. Adequate knowledge about RVF epidemiology will assure food security and public health.

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Sero-positivity and associated intrinsic and extrinsic drivers of Rift Valley fever occurrence in pastoral herds of Nigeria: A cross sectional survey

10.21203/rs.2.15982/v1 ◽

2019 ◽

Author(s):

Nma Bida Alhaji ◽

Jibrin Aminu ◽

Mohammed Kabir Lawan ◽

Olutayo Olajide Babalobi ◽

Ibrahim Ghali-Mohammed ◽

...

Keyword(s):

Rural Areas ◽

Rift Valley ◽

Rift Valley Fever ◽

Animal Movement ◽

Ecological Factors ◽

Categorical Variables ◽

Global Public Health ◽

Cross Sectional ◽

Valley Fever ◽

Cattle Herds

Abstract Background: Rift Valley fever (RVF) is a vector-borne emerging zoonotic disease of animals and humans characterized by major socioeconomic losses to livestock farmers, with potential global public health threat. The study assessed herders’ existing knowledge, sero-prevalence and factors influencing the occurrence of RVF in cattle herds. Methods: A cross-sectional study using questionnaire and determination of IgM was conducted among pastoral herds. Frequencies and proportions were used for descriptive analysis. Categorical variables were presented as proportions and their associations determined by Chi-square tests. Associations were analyzed by univariable tests and multivariable logistic regressions analysis at 95% confidence level. Results: All 403 pastoralists (50.5±15.5 years) participated in this study with the majority of respondents being male, married and had no formal education. The majority of the pastoralists reported low knowledge about zoonotic RVF infections. The within-herd seropositivity of RVF in Nigeria is 5.6% which was higher under nomadic (7.4%) than agro-pastoral (3.8%) settings. All animal demographic characteristics of age, sex and breeds were not significantly (p>0.05) associated with occurrence of RVF in pastoral cattle herds. However, all the socio-ecological factors significantly (p<0.05) influenced RVF occurrence in pastoral settlements. However, availability of mosquitoes in the pastoral environments (OR=7.81; 95% CI: 4.85, 12.37), presence of rivers and streams in grazing fields (OR=10.80; 95% CI: 6.77, 17.34), high rainfall (OR=4.30; 95% CI: 2.74, 6.59), irrigated rice fields (OR=5.14; 95% CI: 3.21, 7.79) and bushy vegetation and (OR=6.11; 95% CI: 3.96, 9.43), animal movement (OR=2.2; 95% CI: 1.45, 3.25) and seasonal variations (OR=2.34; 95% CI: 1.55, 3.51) were more likely to influence RVF occurrence in pastoral herds. Conclusions: This study highlighted low levels of knowledge about RVF among surveyed pastoralists as well as socio-ecological factors contributory to RVF occurrence. This study illustrates recent circulation of RVFV in Nigeria and needs urgent interventions. This challenging gap calls for health education of these vulnerable populations on the socio-economic and health threats of RVF in the remote rural areas of developing countries, especially Africa.

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