Last data update: Dec 02, 2024. (Total: 48272 publications since 2009)
Records 1-26 (of 26 Records) |
Query Trace: Hightower A[original query] |
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Rabies surveillance in the United States during 2012
Dyer JL , Wallace R , Orciari L , Hightower D , Yager P , Blanton JD . J Am Vet Med Assoc 2013 243 (6) 805-15 SUMMARY-During 2012, 49 states and Puerto Rico reported 6,162 rabid animals and 1 human rabies case to the CDC, representing a 2.1% increase from the 6,031 rabid animals and 6 human cases reported in 2011. Approximately 92% of reported rabid animals were wildlife. Relative contributions by the major animal groups were as follows: 1,953 raccoons (31.7%), 1,680 bats (27.3%), 1,539 skunks (25.0%), 340 foxes (5.5%), 257 cats (4.2%), 115 cattle (1.9%), and 84 dogs (1.4%). Compared with 2011, there was a substantial increase in the number of rabid cattle reported. One case of rabies involving a human was reported from California after the patient died abroad. The infection was determined to be a result of a rabies virus variant associated with Tadarida brasiliensis, with exposure occurring in California. |
Elimination of Taenia solium transmission in northern Peru
Garcia HH , Gonzalez AE , Tsang VC , O'Neal SE , Llanos-Zavalaga F , Gonzalvez G , Romero J , Rodriguez S , Moyano LM , Ayvar V , Diaz A , Hightower A , Craig PS , Lightowlers MW , Gauci CG , Leontsini E , Gilman RH . N Engl J Med 2016 374 (24) 2335-44 BACKGROUND: Taeniasis and cysticercosis are major causes of seizures and epilepsy. Infection by the causative parasite Taenia solium requires transmission between humans and pigs. The disease is considered to be eradicable, but data on attempts at regional elimination are lacking. We conducted a three-phase control program in Tumbes, Peru, to determine whether regional elimination would be feasible. METHODS: We systematically tested and compared elimination strategies to show the feasibility of interrupting the transmission of T. solium infection in a region of highly endemic disease in Peru. In phase 1, we assessed the effectiveness and feasibility of six intervention strategies that involved screening of humans and pigs, antiparasitic treatment, prevention education, and pig replacement in 42 villages. In phase 2, we compared mass treatment with mass screening (each either with or without vaccination of pigs) in 17 villages. In phase 3, we implemented the final strategy of mass treatment of humans along with the mass treatment and vaccination of pigs in the entire rural region of Tumbes (107 villages comprising 81,170 people and 55,638 pigs). The effect of the intervention was measured after phases 2 and 3 with the use of detailed necropsy to detect pigs with live, nondegenerated cysts capable of causing new infection. The necropsy sampling was weighted in that we preferentially included more samples from seropositive pigs than from seronegative pigs. RESULTS: Only two of the strategies implemented in phase 1 resulted in limited control over the transmission of T. solium infection, which highlighted the need to intensify the subsequent strategies. After the strategies in phase 2 were implemented, no cyst that was capable of further transmission of T. solium infection was found among 658 sampled pigs. One year later, without further intervention, 7 of 310 sampled pigs had live, nondegenerated cysts, but no infected pig was found in 11 of 17 villages, including all the villages in which mass antiparasitic treatment plus vaccination was implemented. After the final strategy was implemented in phase 3, a total of 3 of 342 pigs had live, nondegenerated cysts, but no infected pig was found in 105 of 107 villages. CONCLUSIONS: We showed that the transmission of T. solium infection was interrupted on a regional scale in a highly endemic region in Peru. (Funded by the Bill and Melinda Gates Foundation and others.). |
Predictive factors and risk mapping for Rift Valley fever epidemics in Kenya
Munyua PM , Murithi RM , Ithondeka P , Hightower A , Thumbi SM , Anyangu SA , Kiplimo J , Bett B , Vrieling A , Breiman RF , Njenga MK . PLoS One 2016 11 (1) e0144570 BACKGROUND: To-date, Rift Valley fever (RVF) outbreaks have occurred in 38 of the 69 administrative districts in Kenya. Using surveillance records collected between 1951 and 2007, we determined the risk of exposure and outcome of an RVF outbreak, examined the ecological and climatic factors associated with the outbreaks, and used these data to develop an RVF risk map for Kenya. METHODS: Exposure to RVF was evaluated as the proportion of the total outbreak years that each district was involved in prior epizootics, whereas risk of outcome was assessed as severity of observed disease in humans and animals for each district. A probability-impact weighted score (1 to 9) of the combined exposure and outcome risks was used to classify a district as high (score ≥ 5) or medium (score ≥2 - <5) risk, a classification that was subsequently subjected to expert group analysis for final risk level determination at the division levels (total = 391 divisions). Divisions that never reported RVF disease (score < 2) were classified as low risk. Using data from the 2006/07 RVF outbreak, the predictive risk factors for an RVF outbreak were identified. The predictive probabilities from the model were further used to develop an RVF risk map for Kenya. RESULTS: The final output was a RVF risk map that classified 101 of 391 divisions (26%) located in 21 districts as high risk, and 100 of 391 divisions (26%) located in 35 districts as medium risk and 190 divisions (48%) as low risk, including all 97 divisions in Nyanza and Western provinces. The risk of RVF was positively associated with Normalized Difference Vegetation Index (NDVI), low altitude below 1000m and high precipitation in areas with solonertz, luvisols and vertisols soil types (p <0.05). CONCLUSION: RVF risk map serves as an important tool for developing and deploying prevention and control measures against the disease. |
The perils of straying from protocol: sampling bias and interviewer effects
Ngongo CJ , Frick KD , Hightower AW , Mathingau FA , Burke H , Breiman RF . PLoS One 2015 10 (2) e0118025 Fidelity to research protocol is critical. In a contingent valuation study in an informal urban settlement in Nairobi, Kenya, participants responded differently to the three trained interviewers. Interviewer effects were present during the survey pilot, then magnified at the start of the main survey after a seemingly slight adaptation of the survey sampling protocol allowed interviewers to speak with the "closest neighbor" in the event that no one was home at a selected household. This slight degree of interviewer choice led to inferred sampling bias. Multinomial logistic regression and post-estimation tests revealed that the three interviewers' samples differed significantly from one another according to six demographic characteristics. The two female interviewers were 2.8 and 7.7 times less likely to talk with respondents of low socio-economic status than the male interviewer. Systematic error renders it impossible to determine which of the survey responses might be "correct." This experience demonstrates why researchers must take care to strictly follow sampling protocols, consistently train interviewers, and monitor responses by interview to ensure similarity between interviewers' groups and produce unbiased estimates of the parameters of interest. |
Acute gastrointestinal illness following a prolonged community-wide water emergency
Gargano JW , Freeland AL , Morrison MA , Stevens K , Zajac L , Wolkon A , Hightower A , Miller MD , Brunkard JM . Epidemiol Infect 2015 143 (13) 1-11 The drinking water infrastructure in the United States is ageing; extreme weather events place additional stress on water systems that can lead to interruptions in the delivery of safe drinking water. We investigated the association between household exposures to water service problems and acute gastrointestinal illness (AGI) and acute respiratory illness (ARI) in Alabama communities that experienced a freeze-related community-wide water emergency. Following the water emergency, investigators conducted a household survey. Logistic regression models were used to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) for self-reported AGI and ARI by water exposures. AGI was higher in households that lost water service for 7 days (aPR 2.4, 95% CI 1.1-5.2) and experienced low water pressure for 7 days (aPR 3.6, 95% CI 1.4-9.0) compared to households that experienced normal service and pressure; prevalence of AGI increased with increasing duration of water service interruptions. Investments in the ageing drinking water infrastructure are needed to prevent future low-pressure events and to maintain uninterrupted access to the fundamental public health protection provided by safe water supplies. Households and communities need to increase their awareness of and preparedness for water emergencies to mitigate adverse health impacts. |
Health care utilization and access to human immunodeficiency virus (HIV) testing and care and treatment services in a rural area with high HIV prevalence, Nyanza Province, Kenya, 2007
Ackers ML , Hightower A , Obor D , Ofware P , Ngere L , Kubaje A , Laserson KF . Am J Trop Med Hyg 2013 90 (2) 224-33 We present health and demographic surveillance system data to assess associations with healthcare use and human immunodeficiency virus (HIV) service receipt in a high HIV prevalence area of western Kenya. Eighty-six percent of 15,302 residents indicated a facility/clinician for routine medical services; 60% reported active (within the past year) attendance. Only 34% reported a previous HIV test, and self-reported HIV prevalence was 6%. Active attendees lived only slightly closer to their reported service site (2.8 versus 3.1 km; P < 0.001) compared with inactive attendees. Multivariate analysis showed that younger respondents (< 30 years of age) and active and inactive attendees were more likely to report an HIV test compared with non-attendees; men were less likely to report HIV testing. Despite traveling farther for HIV services (median distance = 4.4 km), 77% of those disclosing HIV infection reported HIV care enrollment. Men and younger respondents were less likely to enroll in HIV care. Socioeconomic status was not associated with HIV service use. Distance did not appear to be the major barrier to service receipt. The health and demographic surveillance system data identified patterns of service use that are useful for future program planning. |
Assessment of quality of life as a tool for measuring morbidity due to Schistosoma mansoni infection and the impact of treatment
Won KY , Abudho B , Blackstock A , Montgomery SP , Kennedy ED , Person B , Mwinzi PN , Ochola EA , Foo KT , Hightower AW , Karanja DM , Secor WE . Am J Trop Med Hyg 2013 90 (2) 322-8 Recently, health measurements have broadened to include the assessment of quality of life (QOL). This study was conducted to assess whether the short form of the World Health Organization (WHO) QOL questionnaire (WHOQOL-BREF) was an effective tool for measuring morbidity due to Schistosoma mansoni infection and whether it could detect an impact of treatment with praziquantel. A total of 724 adults 18-85 years of age were enrolled. At baseline, S. mansoni prevalence was 73.2% by stool examination and 75.4% by circulating cathodic antigen, and there was no association between infection status and WHOQOL-BREF scores. Six months after treatment, S. mansoni prevalence was lower and the proportion of persons with higher WHOQOL-BREF scores significantly increased among persons who were infected at baseline. However, a similar increase was observed in persons infected at baseline. In areas of high prevalence, the WHOQOL-BREF may not be able to detect the benefits of schistosomiasis control programs. |
The phylogeography and spatiotemporal spread of south-central skunk rabies virus
Kuzmina NA , Lemey P , Kuzmin IV , Mayes BC , Ellison JA , Orciari LA , Hightower D , Taylor ST , Rupprecht CE . PLoS One 2013 8 (12) e82348 The south-central skunk rabies virus (SCSK) is the most broadly distributed terrestrial viral lineage in North America. Skunk rabies has not been efficiently targeted by oral vaccination campaigns and represents a natural system of pathogen invasion, yielding insights to rabies emergence. In the present study we reconstructed spatiotemporal spread of SCSK in the whole territory of its circulation using a combination of Bayesian methods. The analysis based on 241 glycoprotein gene sequences demonstrated that SCSK is much more divergent phylogenetically than was appreciated previously. According to our analyses the SCSK originated in the territory of Texas ~170 years ago, and spread geographically during the following decades. The wavefront velocity in the northward direction was significantly greater than in the eastward and westward directions. Rivers (except the Mississippi River and Rio Grande River) did not constitute significant barriers for epizootic spread, in contrast to deserts and mountains. The mean dispersal rate of skunk rabies was lower than that of the raccoon and fox rabies. Viral lineages circulate in their areas with limited evidence of geographic spread during decades. However, spatiotemporal reconstruction shows that after a long period of stability the dispersal rate and wavefront velocity of SCSK are increasing. Our results indicate that there is a need to develop control measures for SCSK, and suggest how such measure can be implemented most efficiently. Our approach can be extrapolated to other rabies reservoirs and used as a tool for investigation of epizootic patterns and planning interventions towards disease elimination. |
Profile: The KEMRI/CDC Health and Demographic Surveillance System--Western Kenya
Odhiambo FO , Laserson KF , Sewe M , Hamel MJ , Feikin DR , Adazu K , Ogwang S , Obor D , Amek N , Bayoh N , Ombok M , Lindblade K , Desai M , Ter Kuile F , Phillips-Howard P , van Eijk AM , Rosen D , Hightower A , Ofware P , Muttai H , Nahlen B , Decock K , Slutsker L , Breiman RF , Vulule JM . Int J Epidemiol 2012 41 (4) 977-87 The KEMRI/Centers for Disease Control and Prevention (CDC) Health and Demographic Surveillance System (HDSS) is located in Rarieda, Siaya and Gem Districts (Siaya County), lying northeast of Lake Victoria in Nyanza Province, western Kenya. The KEMRI/CDC HDSS, with approximately 220 000 inhabitants, has been the foundation for a variety of studies, including evaluations of insecticide-treated bed nets, burden of diarrhoeal disease and tuberculosis, malaria parasitaemia and anaemia, treatment strategies and immunological correlates of malaria infection, and numerous HIV, tuberculosis, malaria and diarrhoeal disease treatment and vaccine efficacy and effectiveness trials for more than a decade. Current studies include operations research to measure the uptake and effectiveness of the programmatic implementation of integrated malaria control strategies, HIV services, newly introduced vaccines and clinical trials. The HDSS provides general demographic and health information (such as population age structure and density, fertility rates, birth and death rates, in- and out-migrations, patterns of health care access and utilization and the local economics of health care) as well as disease- or intervention-specific information. The HDSS also collects verbal autopsy information on all deaths. Studies take advantage of the sampling frame inherent in the HDSS, whether at individual, household/compound or neighbourhood level. |
Differential association of gene content polymorphisms of killer cell immunoglobulin-like receptors with placental malaria in HIV- and HIV+ mothers.
Omosun YO , Blackstock AJ , Gatei W , Hightower A , van Eijk AM , Ayisi J , Otieno J , Lal RB , Steketee R , Nahlen B , Ter Kuile FO , Slutsker L , Shi YP . PLoS One 2012 7 (6) e38617 Pregnant women have abundant natural killer (NK) cells in their placenta, and NK cell function is regulated by polymorphisms of killer cell immunoglobulin-like receptors (KIRs). Previous studies report different roles of NK cells in the immune responses to placental malaria (PM) and human immunodeficiency virus (HIV-1) infections. Given these references, the aim of this study was to determine the association between KIR gene content polymorphism and PM infection in pregnant women of known HIV-1 status. Sixteen genes in the KIR family were analyzed in 688 pregnant Kenyan women. Gene content polymorphisms were assessed in relation to PM in HIV-1 negative and HIV-1 positive women, respectively. Results showed that in HIV-1 negative women, the presence of the individual genes KIR2DL1 and KIR2DL3 increased the odds of having PM, and the KIR2DL2/KIR2DL2 homozygotes were associated with protection from PM. However, the reverse relationship was observed in HIV-1 positive women, where the presence of individual KIR2DL3 was associated with protection from PM, and KIR2DL2/KIR2DL2 homozygotes increased the odds for susceptibility to PM. Further analysis of the HIV-1 positive women stratified by CD4 counts showed that this reverse association between KIR genes and PM remained only in the individuals with high CD4 cell counts but not in those with low CD4 cell counts. Collectively, these results suggest that inhibitory KIR2DL2 and KIR2DL3, which are alleles of the same locus, play a role in the inverse effects on PM and PM/HIV co-infection and the effect of KIR genes on PM in HIV positive women is dependent on high CD4 cell counts. In addition, analysis of linkage disequilibrium (LD) of the PM relevant KIR genes showed strong LD in women without PM regardless of their HIV status while LD was broken in those with PM, indicating possible selection pressure by malaria infection on the KIR genes. |
Relationship of climate, geography, and geology to the incidence of Rift Valley fever in Kenya during the 2006-2007 outbreak
Hightower A , Kinkade C , Nguku PM , Anyangu A , Mutonga D , Omolo J , Njenga MK , Feikin DR , Schnabel D , Ombok M , Breiman RF . Am J Trop Med Hyg 2012 86 (2) 373-380 We estimated Rift Valley fever (RVF) incidence as a function of geological, geographical, and climatological factors during the 2006-2007 RVF epidemic in Kenya. Location information was obtained for 214 of 340 (63%) confirmed and probable RVF cases that occurred during an outbreak from November 1, 2006 to February 28, 2007. Locations with subtypes of solonetz, calcisols, solonchaks, and planosols soil types were highly associated with RVF occurrence during the outbreak period. Increased rainfall and higher greenness measures before the outbreak were associated with increased risk. RVF was more likely to occur on plains, in densely bushed areas, at lower elevations, and in the Somalia acacia ecological zone. Cases occurred in three spatial temporal clusters that differed by the date of associated rainfall, soil type, and land usage. |
Clinical, epidemiologic, histopathologic and molecular features of an unexplained dermopathy
Pearson ML , Selby JV , Katz KA , Cantrell V , Braden CR , Parise ME , Paddock CD , Lewin-Smith MR , Kalasinsky VF , Goldstein FC , Hightower AW , Papier A , Lewis B , Motipara S , Eberhard ML . PLoS One 2012 7 (1) e29908 BACKGROUND: Morgellons is a poorly characterized constellation of symptoms, with the primary manifestations involving the skin. We conducted an investigation of this unexplained dermopathy to characterize the clinical and epidemiologic features and explore potential etiologies. METHODS: A descriptive study was conducted among persons at least 13 years of age and enrolled in Kaiser Permanente Northern California (KPNC) during 2006-2008. A case was defined as the self-reported emergence of fibers or materials from the skin accompanied by skin lesions and/or disturbing skin sensations. We collected detailed epidemiologic data, performed clinical evaluations and geospatial analyses and analyzed materials collected from participants' skin. RESULTS: We identified 115 case-patients. The prevalence was 3.65 (95% CI = 2.98, 4.40) cases per 100,000 enrollees. There was no clustering of cases within the 13-county KPNC catchment area (p = .113). Case-patients had a median age of 52 years (range: 17-93) and were primarily female (77%) and Caucasian (77%). Multi-system complaints were common; 70% reported chronic fatigue and 54% rated their overall health as fair or poor with mean Physical Component Scores and Mental Component Scores of 36.63 (SD = 12.9) and 35.45 (SD = 12.89), respectively. Cognitive deficits were detected in 59% of case-patients and 63% had evidence of clinically significant somatic complaints; 50% had drugs detected in hair samples and 78% reported exposure to solvents. Solar elastosis was the most common histopathologic abnormality (51% of biopsies); skin lesions were most consistent with arthropod bites or chronic excoriations. No parasites or mycobacteria were detected. Most materials collected from participants’ skin were composed of cellulose, likely of cotton origin. | CONCLUSIONS: This unexplained dermopathy was rare among this population of Northern California residents, but associated with significantly reduced health-related quality of life. No common underlying medical condition or infectious source was identified, similar to more commonly recognized conditions such as delusional infestation. |
Rift Valley fever in Kenya: history of epizootics and identification of vulnerable districts
Murithi RM , Munyua P , Ithondeka PM , Macharia JM , Hightower A , Luman ET , Breiman RF , Njenga MK . Epidemiol Infect 2011 139 (3) 372-80 Since Kenya first reported Rift Valley fever (RVF)-like disease in livestock in 1912, the country has reported the most frequent epizootics of RVF disease. To determine the pattern of disease spread across the country after its introduction in 1912, and to identify regions vulnerable to the periodic epizootics, annual livestock disease records at the Department of Veterinary Services from 1910 to 2007 were analysed in order to document the number and location of RVF-infected livestock herds. A total of 38/69 (55%) administrative districts in the country had reported RVF epizootics by the end of 2007. During the 1912-1950 period, the disease was confined to a district in Rift Valley province that is prone to flooding and where livestock were raised in proximity with wildlife. Between 1951 and 2007, 11 national RVF epizootics were recorded with an average inter-epizootic period of 3.6 years (range 1-7 years); in addition, all epizootics occurred in years when the average annual rainfall increased by more than 50% in the affected districts. Whereas the first two national epizootics in 1951 and 1955 were confined to eight districts in the Rift Valley province, there was a sustained epizootic between 1961 and 1964 that spread the virus to over 30% of the districts across six out of eight provinces. The Western and Nyanza provinces, located on the southwestern region of the country, had never reported RVF infections by 2007. The probability of a district being involved in a national epizootic was fivefold higher (62%) in districts that had previously reported disease compared to districts that had no prior disease activity (11%). These findings suggests that once introduced into certain permissive ecologies, the RVF virus becomes enzootic, making the region vulnerable to periodic epizootics that were probably precipitated by amplification of resident virus associated with heavy rainfall and flooding. |
Factors associated with HIV infection in married or cohabitating couples in Kenya: results from a nationally representative study
Kaiser R , Bunnell R , Hightower A , Kim AA , Cherutich P , Mwangi M , Oluoch T , Dadabhai S , Mureithi P , Mugo N , Mermin J . PLoS One 2011 6 (3) e17842 BACKGROUND: In order to inform prevention programming, we analyzed HIV discordance and concordance within couples in the Kenya AIDS Indicator Survey (KAIS) 2007. METHODS: KAIS was a nationally representative population-based sero-survey that examined demographic and behavioral indicators and serologic testing for HIV, HSV-2, syphilis, and CD4 cell counts in 15,853 consenting adults aged 15-64 years. We analyzed interview and blood testing data at the sexual partnership level from married or cohabitating couples. Multivariable regression models were used to identify factors independently associated with HIV discordant and concordant status. RESULTS: Of 3256 couples identified in the survey, 2748 (84.4%) had interview and blood testing data. Overall, 3.8% of couples were concordantly infected with HIV, and in 5.8% one partner was infected, translating to 338,000 discordant couples in Kenya. In 83.6% of HIV-infected Kenyans living in married or cohabitating couples neither partner knew their HIV status. Factors independently associated with HIV-discordance included young age in women (AOR 1.5, 95% CI: 1.2-1.8; p<0.0001), increasing number of lifetime sexual partners in women (AOR 1.5, 95% CI: 1.3-1.8; p<0.0001), HSV-2 infection in either or both partners (AOR 4.1, 95% CI: 2.3-7.2; p<0.0001), and lack of male circumcision (AOR 1.6, 95% CI: 1.0-2.5; p = 0.032). Independent factors for HIV-concordance included HSV-2 infection in both partners (AOR 6.5, 95% CI: 2.3-18.7; p = 0.001) and lack of male circumcision (AOR 1.8, 95% CI: 1.0-3.3; p = 0.043). CONCLUSIONS: Couple prevention interventions should begin early in relationships and include mutual knowledge of HIV status, reduction of outside sexual partners, and promotion of male circumcision among HIV-uninfected men. Mechanisms for effective prevention or suppression of HSV-2 infection are also needed. |
Sequential Rift Valley fever outbreaks in eastern Africa caused by multiple lineages of the virus
Nderitu L , Lee JS , Omolo J , Omulo S , O'Guinn ML , Hightower A , Mosha F , Mohamed M , Munyua P , Nganga Z , Hiett K , Seal B , Feikin DR , Breiman RF , Njenga MK . J Infect Dis 2011 203 (5) 655-65 BACKGROUND: During the Rift Valley fever (RVF) epidemic of 2006-2007 in eastern Africa, spatial mapping of the outbreaks across Kenya, Somalia, and Tanzania was performed and the RVF viruses were isolated and genetically characterized. METHODS: Following confirmation of the RVF epidemic in Kenya on 19 December 2006 and in Tanzania on 2 February 2007, teams were sent to the field for case finding. Human, livestock, and mosquito specimens were collected and viruses isolated. The World Health Organization response team in Kenya worked with the WHO's polio surveillance team inside Somalia to collect information and specimens from Somalia. RESULTS: Seven geographical foci that reported hundreds of livestock and >25 cases in humans between December 2006 and June 2007 were identified. The onset of RVF cases in each epidemic focus was preceded by heavy rainfall and flooding for at least 10 days. Full-length genome analysis of 16 RVF virus isolates recovered from humans, livestock, and mosquitoes in 5 of the 7 outbreak foci revealed 3 distinct lineages of the viruses within and across outbreak foci. CONCLUSION: The findings indicate that the sequential RVF epidemics in the region were caused by multiple lineages of the RVF virus, sometimes independently activated or introduced in distinct outbreak foci. |
Rapid scale-up of long-lasting insecticide-treated bed nets through integration into the national immunization program during Child Health Week in Togo, 2004
Wolkon A , Vanden Eng JL , Morgah K , Eliades MJ , Thwing J , Terlouw DJ , Takpa V , Dare A , Sodahlon YK , Doumanou Y , Hightower AW , Lama M , Thawani N , Slutsker L , Hawley WA . Am J Trop Med Hyg 2010 83 (5) 1014-9 In December 2004, Togo was the first country to conduct a nationwide free insecticide-treated net (ITN) distribution as part of its National Integrated Child Health Campaign. Community-based cross-sectional surveys were conducted one and nine months post-campaign as part of a multidisciplinary evaluation of the nationwide distribution of ITNs to children 9-59 months of age to evaluate ITN ownership, equity, and use. Our results demonstrated that at one month post-campaign, 93.1% of all eligible children received an ITN. Household ITN ownership and equity increased significantly post-campaign. Nine months post-campaign, 78.6% of households with a child eligible to participate in the campaign retained at least one campaign net. Use by eligible children was 43.5% at one month post-campaign (during the dry season) and 52.9% at nine months post-campaign (during the rainy season). Household ownership of at least one ITN increased from 8.0% pre-campaign to 62.5% one month post-campaign. Together, these findings demonstrate that in this setting, increased household ITN ownership, equity, and retention can be achieved on a national scale through free ITN distribution during an integrated campaign. |
Rift Valley fever outbreak in livestock in Kenya, 2006-2007
Munyua P , Murithi RM , Wainwright S , Githinji J , Hightower A , Mutonga D , Macharia J , Ithondeka PM , Musaa J , Breiman RF , Bloland P , Njenga MK . Am J Trop Med Hyg 2010 83 58-64 We analyzed the extent of livestock involvement in the latest Rift Valley fever (RVF) outbreak in Kenya that started in December 2006 and continued until June 2007. When compared with previous RVF outbreaks in the country, the 2006-07 outbreak was the most extensive in cattle, sheep, goats, and camels affecting thousands of animals in 29 of 69 administrative districts across six of the eight provinces. This contrasted with the distribution of approximately 700 human RVF cases in the country, where over 85% of these cases were located in four districts; Garissa and Ijara districts in Northeastern Province, Baringo district in Rift Valley Province, and Kilifi district in Coast Province. Analysis of livestock and human data suggests that livestock infections occur before virus detection in humans, as supported by clustering of human RVF cases around livestock cases in Baringo district. The highest livestock morbidity and mortality rates were recorded in Garissa and Baringo districts, the same districts that recorded a high number of human cases. The districts that reported RVF in livestock for the first time in 2006/07 included Kitui, Tharaka, Meru South, Meru central, Mwingi, Embu, and Mbeere in Eastern Province, Malindi and Taita taveta in Coast Province, Kirinyaga and Murang'a in Central Province, and Baringo and Samburu in Rift Valley Province, indicating that the disease was occurring in new regions in the country. |
Piloting the use of personal digital assistants for tuberculosis and human immunodeficiency virus surveillance, Kenya, 2007
Auld AF , Wambua N , Onyango J , Marston B , Namulanda G , Ackers M , Oluoch T , Karisa A , Hightower A , Shiraishi RW , Nakashima A , Sitienei J . Int J Tuberc Lung Dis 2010 14 (9) 1140-6 SETTING: Improved documentation of human immunodeficiency virus (HIV) testing and care among tuberculosis (TB) patients is needed to strengthen TB-HIV programs. In 2007, Kenya piloted the use of personal digital assistants (PDAs) instead of paper registers to collect TB-HIV surveillance data from TB clinics. OBJECTIVE: To evaluate the acceptability, data quality and usefulness of PDAs. DESIGN: We interviewed four of 31 district coordinators who collected data in PDAs for patients initiating TB treatment from April to June 2007. In 10 of 93 clinics, we randomly selected patient records for comparison with corresponding records in paper registers or PDAs. Using Cochran-Mantel-Haenszel tests, we compared missing data proportions in paper registers with PDAs. We evaluated PDA usefulness by analyzing PDA data from all 93 clinics. RESULTS: PDAs were well accepted. Patient records were more frequently missing (28/97 vs. 1/112, P < 0.001) and data fields more frequently incomplete (148/1449 vs. 167/2331, P = 0.03) in PDAs compared with paper registers. PDAs, however, facilitated clinic-level analyses: 48/93 (52%) clinics were not reaching the targets of testing ≥80% of TB patients for HIV, and 8 (9%) clinics were providing <80% of TB-HIV co-infected patients with cotrimoxazole (CTX). CONCLUSION: PDAs had high rates of missing data but helped identify clinics that were undertesting for HIV or underprescribing CTX. |
Prediction, assessment of the Rift Valley fever activity in East and Southern Africa 2006-2008 and possible vector control strategies
Anyamba A , Linthicum KJ , Small J , Britch SC , Pak E , de La Rocque S , Formenty P , Hightower AW , Breiman RF , Chretien JP , Tucker CJ , Schnabel D , Sang R , Haagsma K , Latham M , Lewandowski HB , Magdi SO , Mohamed MA , Nguku PM , Reynes JM , Swanepoel R . Am J Trop Med Hyg 2010 83 43-51 Historical outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns of the El Nino/Southern Oscillation (ENSO) phenomenon, which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite measurements of global and regional elevated sea surface temperatures, elevated rainfall, and satellite derived-normalized difference vegetation index data, we predicted with lead times of 2-4 months areas where outbreaks of RVF in humans and animals were expected and occurred in the Horn of Africa, Sudan, and Southern Africa at different time periods from September 2006 to March 2008. Predictions were confirmed by entomological field investigations of virus activity and by reported cases of RVF in human and livestock populations. This represents the first series of prospective predictions of RVF outbreaks and provides a baseline for improved early warning, control, response planning, and mitigation into the future. |
An investigation of a major outbreak of Rift Valley fever in Kenya: 2006-2007
Nguku PM , Sharif SK , Mutonga D , Amwayi S , Omolo J , Mohammed O , Farnon EC , Gould LH , Lederman E , Rao C , Sang R , Schnabel D , Feikin DR , Hightower A , Njenga MK , Breiman RF . Am J Trop Med Hyg 2010 83 5-13 An outbreak of Rift Valley fever (RVF) occurred in Kenya during November 2006 through March 2007. We characterized the magnitude of the outbreak through disease surveillance and serosurveys, and investigated contributing factors to enhance strategies for forecasting to prevent or minimize the impact of future outbreaks. Of 700 suspected cases, 392 met probable or confirmed case definitions; demographic data were available for 340 (87%), including 90 (26.4%) deaths. Male cases were more likely to die than females, Case Fatality Rate Ratio 1.8 (95% Confidence Interval [CI] 1.3-3.8). Serosurveys suggested an attack rate up to 13% of residents in heavily affected areas. Genetic sequencing showed high homology among viruses from this and earlier RVF outbreaks. Case areas were more likely than non-case areas to have soil types that retain surface moisture. The outbreak had a devastatingly high case-fatality rate for hospitalized patients. However, there were up to 180,000 infected mildly ill or asymptomatic people within highly affected areas. Soil type data may add specificity to climate-based forecasting models for RVF. |
Risk factors for severe Rift Valley fever infection in Kenya, 2007
Anyangu AS , Gould LH , Sharif SK , Nguku PM , Omolo JO , Mutonga D , Rao CY , Lederman ER , Schnabel D , Paweska JT , Katz M , Hightower A , Njenga MK , Feikin DR , Breiman RF . Am J Trop Med Hyg 2010 83 14-21 A large Rift Valley fever (RVF) outbreak occurred in Kenya from December 2006 to March 2007. We conducted a study to define risk factors associated with infection and severe disease. A total of 861 individuals from 424 households were enrolled. Two hundred and two participants (23%) had serologic evidence of acute RVF infection. Of these, 52 (26%) had severe RVF disease characterized by hemorrhagic manifestations or death. Independent risk factors for acute RVF infection were consuming or handling products from sick animals (odds ratio [OR] = 2.53, 95% confidence interval [CI] = 1.78-3.61, population attributable risk percentage [PAR%] = 19%) and being a herds person (OR 1.77, 95% CI = 1.20-2.63, PAR% = 11%). Touching an aborted animal fetus was associated with severe RVF disease (OR = 3.83, 95% CI = 1.68-9.07, PAR% = 14%). Consuming or handling products from sick animals was associated with death (OR = 3.67, 95% CI = 1.07-12.64, PAR% = 47%). Exposures related to animal contact were associated with acute RVF infection, whereas exposures to mosquitoes were not independent risk factors. |
Bed net ownership in Kenya: the impact of 3.4 million free bed nets
Hightower A , Kiptui R , Manya A , Wolkon A , Vanden Eng J , Hamel M , Noor A , Sharif SK , Buluma R , Vulule J , Laserson K , Slutsker L , Akhwale W . Malar J 2010 9 (1) 183 BACKGROUND: In July and September 2006, 3.4 million long-lasting insecticide-treated bed nets (LLINs) were distributed free in a campaign targeting children 0-59 months old (CU5s) in the 46 districts with malaria in Kenya. A survey was conducted one month after the distribution to evaluate who received campaign LLINs, who owned insecticide-treated bed nets and other bed nets received through other channels, and how these nets were being used. The feasibility of a distribution strategy aimed at a high-risk target group to meet bed net ownership and usage targets is evaluated. METHODS: A stratified, two-stage cluster survey sampled districts and enumeration areas with probability proportional to size. Handheld computers (PDAs) with attached global positioning systems (GPS) were used to develop the sampling frame, guide interviewers back to chosen households, and collect survey data. RESULTS: In targeted areas, 67.5% (95% CI: 64.6, 70.3%) of all households with CU5s received campaign LLINs. Including previously owned nets, 74.4 % (95% CI: 71.8, 77.0%) of all households with CU5s had an ITN. Over half of CU5s (51.7% , 95% CI: 48.8, 54.7%) slept under an ITN during the previous evening. Nearly forty percent (39.1%) of all households received a campaign net, elevating overall household ownership of ITNs to 50.7% (95% CI: 48.4, 52.9 %). CONCLUSIONS: The campaign was successful in reaching the target population, families with CU5s, the risk group most vulnerable to malaria. Targeted distribution strategies will help Kenya approach indicator targets, but will need to be combined with other strategies to achieve desired population coverage levels. |
Assessing bed net use and non-use after long-lasting insecticidal net distribution: a simple framework to guide programmatic strategies
Vanden Eng JL , Thwing J , Wolkon A , Kulkarni MA , Manya A , Erskine M , Hightower A , Slutsker L . Malar J 2010 9 (1) 133 BACKGROUND: Insecticide-treated nets (ITNs) are becoming increasingly available to vulnerable populations at risk for malaria. Their appropriate and consistent use is essential to preventing malaria, but ITN use often lags behind ITN ownership. In order to increase ITN use, it is necessary to devise strategies that accurately identify, differentiate, and target the reasons and types of non-use. METHODS: A simple method based on the end-user as the denominator was employed to classify each individual into one of four ITN use categories: 1) living in households not owning an ITN; 2) living in households owning, but not hanging an ITN; 3) living in households owning and hanging an ITN, but who are not sleeping under one; and 4) sleeping under an ITN. This framework was applied to survey data designed to evaluate long-lasting insecticidal nets (LLINs) distributions following integrated campaigns in five countries: Togo, Sierra Leone, Madagascar, Kenya and Niger. RESULTS: The percentage of children <5 years of age sleeping under an ITN ranged from 51.5% in Kenya to 81.1% in Madagascar. Among the three categories of non-use, children living in households without an ITN make up largest group (range: 9.4%-30.0%), despite the efforts of the integrated child health campaigns. The percentage of children who live in households that own but do not hang an ITN ranged from 5.1% to 16.1%. The percentage of children living in households where an ITN was suspended, but who were not sleeping under it ranged from 4.3% to 16.4%. Use by all household members in Sierra Leone (39.9%) and Madagascar (60.4%) indicate that integrated campaigns reach beyond their desired target populations. CONCLUSIONS: The framework outlined in this paper provides a helpful tool to examine the deficiencies in ITN use. Monitoring and evaluation strategies designed to assess ITN ownership and use can easily incorporate this approach using existing data collection instruments that measure the standard indicators. |
Geospatial distribution and determinants of child mortality in rural western Kenya 2002-2005
Ombok M , Adazu K , Odhiambo F , Bayoh N , Kiriinya R , Slutsker L , Hamel MJ , Williamson J , Hightower A , Laserson KF , Feikin DR . Trop Med Int Health 2010 15 (4) 423-33 OBJECTIVE: To describe local geospatial variation and geospatial risk factors for child mortality in rural western Kenya. METHODS: We calculated under-5 mortality rates (U5MR) in 217 villages in a Health and Demographic Surveillance System (HDSS) area in western Kenya from 1 May 2002 through 31 December 2005. U5MRs by village were mapped. Geographical positioning system coordinates of residences at the time of death and distances to nearby locations were calculated. Multivariable Poisson regression accounting for clustering at the compound level was used to evaluate the association of geospatial factors and mortality for infants and children aged 1-4 years. RESULTS: Among 54 057 children, the overall U5MR was 56.5 per 1000 person-years and varied by village from 21 to 177 per 1000 person-years. High mortality villages occurred in clusters by location and remained in the highest mortality quintile over several years. In multivariable analysis, controlling for maternal age and education as well as household crowding, higher infant mortality was associated with living closer to streams and further from public transport roads. For children 1-4 years, living at middle elevations (1280-1332 metres), living within lower population densities areas, and living in the northern section of the HDSS were associated with higher mortality. CONCLUSIONS: Childhood mortality was significantly higher in some villages. Several geospatial factors were associated with mortality, which might indicate variability in access to health care or exposure and transmission of infectious diseases. These results are useful in prioritising areas for further study and implementing directed public health interventions. |
A peer-led HIV counselling and testing programme for the deaf in Kenya
Taegtmeyer M , Hightower A , Opiyo W , Mwachiro L , Henderson K , Angala P , Ngare C , Marum E . Disabil Rehabil 2009 31 (6) 508-14 PURPOSE: To describe and evaluate the establishment of the first VCT services for the Deaf in Africa. METHOD: Operational research methods were used to document programme establishment. The demographics of deaf VCT clients were compared with hearing clients at the same sites as well as where clients had learned of the service, HIV risks, and HIV test results. Univariate and multivariate analyses were used. RESULTS: During the two year period (January 2004 to December 2005) 1709 Deaf and 1649 hearing clients were seen at three Deaf VCT sites. The majority of Deaf clients in this sample learned of the services through the peer education programme. Data indicate that Deaf VCT clients are as much at risk of HIV from sexual transmission as their hearing counterparts and that Deaf persons seeking VCT services have an HIV prevalence of 7%, similar to the national rate of 6.7%. CONCLUSIONS: The Deaf in Kenya are at risk of HIV and there is an urgent need for Deaf-friendly HIV services, supplemented by peer education programmes. This is the first published report describing HIV services run by the Deaf for the Deaf in the developing world. |
HIV prevalence and associated risk factors among individuals aged 13-34 years in rural Western Kenya
Amornkul PN , Vandenhoudt H , Nasokho P , Odhiambo F , Mwaengo D , Hightower A , Buve A , Misore A , Vulule J , Vitek C , Glynn J , Greenberg A , Slutsker L , De Cock KM . PLoS One 2009 4 (7) e6470 OBJECTIVES: To estimate HIV prevalence and characterize risk factors among young adults in Asembo, rural western Kenya. DESIGN: Community-based cross-sectional survey. METHODS: From a demographic surveillance system, we selected a random sample of residents aged 13-34 years, who were contacted at home and invited to a nearby mobile study site. Consent procedures for non-emancipated minors required assent and parental consent. From October 2003 - April 2004, consenting participants were interviewed on risk behavior and tested for HIV and HSV-2. HIV voluntary counseling and testing was offered. RESULTS: Of 2606 eligible residents, 1822 (70%) enrolled. Primary reasons for refusal included not wanting blood taken, not wanting to learn HIV status, and partner/parental objection. Females comprised 53% of 1762 participants providing blood. Adjusted HIV prevalence was 15.4% overall: 20.5% among females and 10.2% among males. HIV prevalence was highest in women aged 25-29 years (36.5%) and men aged 30-34 years (41.1%). HSV-2 prevalence was 40.0% overall: 53% among females, 25.8% among males. In multivariate models stratified by gender and marital status, HIV infection was strongly associated with age, higher number of sex partners, widowhood, and HSV-2 seropositivity. CONCLUSIONS: Asembo has extremely high HIV and HSV-2 prevalence, and probable high incidence, among young adults. Further research on circumstances around HIV acquisition in young women and novel prevention strategies (vaccines, microbicides, pre-exposure prophylaxis, HSV-2 prevention, etc.) are urgently needed. |
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