Epidemiologic and Environmental Risk Factors of Rift Valley Fever in Southern Africa from 2008 to 2011

Background: Rift Valley fever (RVF) outbreaks have been associated with periods of widespread and above normal rainfall over several months. Knowledge on the environmental factors influencing disease transmission dynamics has provided the basis for developing models to predict RVF outbreaks in Africa. From 2008 to 2011, South Africa experienced the worst wave of RVF outbreaks in almost 40 years. We investigated rainfall associated environmental factors in southern Africa preceding these outbreaks. Methods: RVF epizootic records obtained from the World Animal Health Information Database (WAHID), documenting livestock species affected, location, and time, were analyzed. Environmental variables including rainfall and satellite-derived normalized difference vegetation index (NDVI) data were collected and assessed in outbreak regions to understand the underlying drivers of the outbreaks. Results: The predominant domestic vertebrate species affected in 2008 and 2009 were cattle, when outbreaks were concentrated in the eastern provinces of South Africa. In 2010 and 2011, outbreaks occurred in the interior and southern provinces affecting over 16,000 sheep. The highest number of cases occurred between January and April but epidemics occurred in different regions every year, moving from the northeast of South Africa toward the southwest with each progressing year. The outbreaks showed a pattern of increased rainfall preceding epizootics ranging from 9 to 152 days; however, NDVI and rainfall were less correlated with the start of the outbreaks than has been observed in eastern Africa. Conclusions: Analyses of the multiyear RVF outbreaks of 2008 to 2011 in South Africa indicated that rainfall, NDVI, and other environmental and geographical factors, such as land use, drainage, and topography, play a role in disease emergence. Current and future investigations into these factors will be able to contribute to improving spatial accuracy of models to map risk areas, allowing adequate time for preparation and prevention before an outbreak occurs

The experience of care partners of patients with Parkinson's disease psychosis.

BackgroundParkinson's disease psychosis (PDP) has a major impact on quality of life and care partner burden; however, little is known about the lived experiences of care partners in managing PDP.ObjectiveTo understand how care partners of individuals with PDP experience their role and articulate their needs related to psychosis.MethodsThis was a qualitative study of semi-structured telephone interviews. Recruitment was conducted online via the clinical study matching tool, Fox Trial Finder; study activities took place remotely via telephone interviews. Transcripts of the phone interviews were analyzed by grounded theory methods, and a codebook of key themes that emerged from the analysis was developed.ResultsNine care partners (all female) were interviewed. Discussion topics in the codebook included (1) care partner burden and guilt; (2) communication with medical professionals; (3) coping strategies; (4) emotional reactions of the care partner to psychosis; (5) sources of knowledge about PD psychosis; (6) attitudes towards medications for PDP; (7) strategies to care for loved ones with psychosis; (8) psychosis triggers.ConclusionsThis qualitative analysis uncovers important aspects of the care partner experience, including challenges in navigating the medical system and communicating with professionals. Providers treating patients with PDP should be aware of these constraints and provide added support for strained care partners

Comparison of enzyme-linked immunosorbent assay systems using rift valley fever virus nucleocapsid protein and inactivated virus as antigens

BACKGROUND: Rift Valley Fever(RVF)is a mosquito-borne viral zoonosis.To detect RVF virus(RVFV)infection,indirect immunoglobulin G(IgG)and immunoglobulin M(IgM)enzyme linked immunosorbent assays(ELISAs)which utilize recombinant RVFV nucleocapsid(RVFV-N)protein as assay antigen, have reportedly been used, however, there is still a need to develop more sensitive and specific methods of detection. METHODS: RVFV-N protein was expressed in Escherichia coli (E. coli) and purified by histidine-tag based affinity chromatography. This recombinant RVFV-N (rRVFV-N) protein was then used as antigen to develop an IgG sandwich ELISA and IgM capture ELISAs for human sera. Ninety six serum samples collected from healthy volunteers during the RVF surveillance programme in Kenya in 2013, and 93 serum samples collected from RVF-suspected patients during the 2006-2007 RVF outbreak in Kenya were used respectively, to evaluate the newly established rRVFV-N protein-based IgG sandwich ELISA and IgM capture ELISA systems in comparison with the inactivated virus-based ELISA systems. RESULTS: rRVFV-N protein-based-IgG sandwich ELISA and IgM capture ELISA for human sera were established.Both the new ELISA systems were in 100% concordance with the inactivated virus-based ELISA systems, with a sensitivity and specificity of 100%. CONCLUSIONS: Recombinant RVFV-N is a safe and affordable antigen for RVF diagnosis.Our rRVFV-N-based ELISA systems are safe and reliable tools for diagnosis of RVFV infection in humans and especially useful in large-scale epidemiological investigation and for application in developing countries