• 1.

    Wesolowski A, Eagle N, Tatem AJ, Smith DL, Noor AM, Snow RW, Buckee CO, 2012. Quantifying the impact of human mobility on malaria. Science 338: 267270.

  • 2.

    National Centers for Environmental Information (NCEI) , 2019. Climate Data Online (CDO). Available at: https://www.ncdc.noaa.gov/cdo-web/. Accessed February 17, 2019.

  • 3.

    United Nations , 2016. Turkana County & UN Joint Integrated Area-based Development Programme. Available at: www.ke.one.un.org. Accessed November 28, 2020.

  • 4.

    WorldPop , 2019. WorldPop. Available at: https://www.worldpop.org/. Accessed February 17, 2019.

  • 5.

    Kenya Food Security Steering Group, Turkana County Steering Group , 2018. Turkana County 2018 Long Rains Food Security Assessment Report Vol. 1. Available at: http://www.ndma.go.ke/index.php/resource-center/send/59-2018/4966-turkana-county-lra-2018-report-final. Accessed February 5, 2019.

  • 6.

    Little MA, Dyson-Hudson R, McCabe JT, Little MA & Leslie PW Oxford, UK: Oxford University Press.

  • 7.

    Snow RW, Okiro EA, Noor AM, Munguti K, Tetteh G, Juma E, 2009. The coverage and impact of malaria intervention in Kenya 2007–2009. Division of Malaria Control, Ministry of Public Health and Sanitation.

  • 8.

    Malaria Atlas Project, 2021. The Malaria Atlas Project. Available at: https://malariaatlas.org/. Accessed February 25, 2021.

  • 9.

    Ministry of Health, 2016. The epidemiology and control profile of malaria in Kenya: reviewing the evidence to guide the future vector control. National Malaria Control Programme, Ministry of Health. Technical support provided by the LINK Project (London School of Hygiene and Tropical Medicine and the Information for Malaria (INFORM) Project, KEMRI-Wellcome Trust Research Programme), Nairobi, Kenya.

  • 10.

    MSF , 2019. MSF Responds to Malaria Outbreak in Turkana, Kenya. Available at: https://msf.or.ke/en/magazine/msf-responds-malaria-outbreak-turkana-kenya. Accessed October 16, 2019.

  • 11.

    Mulambalah C, 2018. An evolving malaria epidemic in Kenya: a regional alert. CHRISMED J Heal Res 5: 162.

  • 12.

    Agade KM, 2014. Ungoverned space’ and the oil find in Turkana. Round Table 103: 497515.

  • 13.

    Snyder DE, Wiseman S, Cruthers LR, Slone RL, 2011. Ivermectin and milbemycin oxime in experimental adult heartworm (Dirofilaria immitis) infection of dogs. J Vet Intern Med 25: 6164.

    • Search Google Scholar
    • Export Citation
  • 14.

    Avery S, 2012. Lake Turkana and the Lower Omo: Hydrological Impacts of Major Dam and Irrigation Developments. Available at: https://www.africanstudies.ox.ac.uk/sites/default/files/africanstudies/documents/media/executive_summary_introduction.pdf. Accessed November 28, 2020.

  • 15.

    UNESCO , 2013. Strategic Groundwater Reserves Found in Northern Kenya. UNESCOPRESS. Available at: http://www.unesco.org/new/en/media-services/single-view/news/strategic_groundwater_reserves_found_in_northern_kenya/#.VYGqtfmqqko. Accessed December 19, 2020.

  • 16.

    Okell LC, Ghani AC, Lyons E, Drakeley CJ, 2009. Submicroscopic Infection in Plasmodium falciparum-endemic populations: a systematic review and meta-analysis. 1509, doi: .

    • Crossref
    • Export Citation
  • 17.

    Roper C, Elhassan IM, Hviid L, Giha H, Richardson W, Babiker H, Satti GMH, Theander TG, Arnot DE, 1996. Detection of very low level Plasmodium falciparum infections using the nested polymerase chain reaction and a reassessment of the epidemiology of unstable malaria in Sudan. Am J Trop Med Hyg 54: 325331.

    • Search Google Scholar
    • Export Citation
  • 18.

    Baeza A, Bouma MJ, Dhiman RC, Baskerville EB, Ceccato P, Yadav RS, Pascual M, 2013. Long-lasting transition toward sustainable elimination of desert malaria under irrigation development. Proc Natl Acad Sci USA 110: 1515715162.

    • Search Google Scholar
    • Export Citation
  • 19.

    Garg A, Dhiman RC, Bhattacharya S, Shukla PR, 2009. Development, malaria and adaptation to climate change: a case study from India. Environ Manage 43: 779789.

    • Search Google Scholar
    • Export Citation
  • 20.

    Kenya National Bureau of Statistics , 2019. Distribution of Population by Administrative Units: 2019 Kenya Population and Housing Census Vol 2. Available at: http://www.knbs.or.ke.

  • 21.

    Taylor SM, Sumner KM, Freedman B, Mangeni JN, Obala AA, O’Meara WP, 2019. Direct estimation of sensitivity of Plasmodium falciparum rapid diagnostic test for active case detection in a high-transmission community setting. Am J Trop Med Hyg 101: 14161423.

    • Search Google Scholar
    • Export Citation
  • 22.

    World Health Organization , 2017. Achieving and Maintaining Universal Coverage with Long-lasting Insecticidal Nets for Malaria Control. (No. WHO/HTM/GMP/2017.20). World Health Organization.

  • 23.

    Aidoo EK et al., 2018. Reactive case detection of Plasmodium falciparum in western Kenya highlands: effective in identifying additional cases, yet limited effect on transmission. Malar J 17: 111.

    • Search Google Scholar
    • Export Citation
  • 24.

    Hustedt J et al., 2016. Reactive case-detection of malaria in Pailin Province, western Cambodia: lessons from a year-long evaluation in a pre-elimination setting. Malar J 15: 132.

    • Search Google Scholar
    • Export Citation
  • 25.

    Sturrock HJW, Novotny JM, Kunene S, Dlamini S, Zulu Z, Cohen JM, Hsiang MS, Greenhouse B, Gosling RD, 2013. Reactive case detection for malaria elimination: real-life experience from an ongoing program in Swaziland. PLoS One 8: e63830.

    • Search Google Scholar
    • Export Citation
  • 26.

    Steinhardt LC et al., 2017. Effectiveness of insecticide-treated bednets in malaria prevention in Haiti: a case-control study. Lancet Glob Health 5: e96e103.

    • Search Google Scholar
    • Export Citation
  • 27.

    Kibret S, Alemu Y, Boelee E, Tekie H, Alemu D, Petros B, 2010. The impact of a small-scale irrigation scheme on malaria transmission in Ziway area, central Ethiopia. Trop Med Int Health 15: 4150.

    • Search Google Scholar
    • Export Citation
  • 28.

    Coldiron ME, Von Seidlein L, Grais RF, 2017. Seasonal malaria chemoprevention: Successes and missed opportunities. Malar J 16: 481.

  • 29.

    Guler JL, Rosenthal PJ, 2019. Mass drug administration to control and eliminate malaria in Africa: how do we best utilize the tools at hand? Clin Infect Dis 69: 287289.

    • Search Google Scholar
    • Export Citation
  • 30.

    Hsiang MS et al., 2020. Active case finding for malaria: a 3-year national evaluation of optimal approaches to detect infections and hotspots through reactive case detection in the low-transmission setting of Eswatini. Clin Infect Dis 70: 13161325.

    • Search Google Scholar
    • Export Citation
  • 31.

    Hsiang MS et al., 2020. Effectiveness of reactive focal mass drug administration and reactive focal vector control to reduce malaria transmission in the low malaria-endemic setting of Namibia: a cluster-randomised controlled, open-label, two-by-two factorial design trial. Lancet 395: 13611373.

    • Search Google Scholar
    • Export Citation
  • 32.

    Bennett A et al., 2020. A longitudinal cohort to monitor malaria infection incidence during mass drug administration in Southern Province, Zambia. Am J Trop Med Hyg 103: 5465.

    • Search Google Scholar
    • Export Citation
  • 33.

    Stresman G, Whittaker C, Slater HC, Bousema T, Cook J, 2020. Quantifying Plasmodium falciparum infections clustering within households to inform household-based intervention strategies for malaria control programs: an observational study and meta-analysis from 41 malaria-endemic countries. PLoS Med 17: e1003370.

    • Search Google Scholar
    • Export Citation
  • 34.

    Elgoraish AG, Elzaki SEG, Ahmed RTE, Ahmed AI, Fadlalmula HA, Abdalgader Mohamed S, Abdallah NI, Abdelgadir O, Ageep TB, El-Sayed BB, 2019. Epidemiology and distribution of Plasmodium vivax malaria in Sudan. Trans R Soc Trop Med Hyg 113: 517524.

    • Search Google Scholar
    • Export Citation
  • 35.

    Deress T, Girma M, 2019. Plasmodium falciparum and Plasmodium vivax prevalence in Ethiopia: a systematic review and meta-analysis. Malar Res Treat 2019: 7065064.

    • Search Google Scholar
    • Export Citation
 
 
 

 

 
 
 

 

 

 

 

 

 

Epidemiology of Plasmodium falciparum Infections in a Semi-Arid Rural African Setting: Evidence from Reactive Case Detection in Northwestern Kenya

View More View Less
  • 1 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland;
  • | 2 Department of Epidemiology and Medical Statistics, School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya;
  • | 3 Department of Health Services and Sanitation, Turkana County, Kenya;
  • | 4 Academic Model Providing Access to Healthcare, Eldoret, Kenya;
  • | 5 Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina;
  • | 6 Lodwar County Referral Hospital, Turkana County, Kenya;
  • | 7 Duke Global Health Institute, Duke University, Durham, North Carolina;
  • | 8 School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya

ABSTRACT.

In northwestern Kenya, Turkana County has been historically considered unsuitable for stable malaria transmission because of its unfavorable climate and predominantly semi-nomadic population; consequently, it is overlooked during malaria control planning. However, the area is changing, with substantial development, an upsurge in travel associated with resource extraction, and more populated settlements forming. Recently, numerous malaria outbreaks have highlighted the need to characterize malaria transmission and its associated risk factors in the region to inform control strategies. Reactive case detection of confirmed malaria cases at six health facilities across central Turkana was conducted from 2018 to 2019. Infections in household members of index cases were detected by malaria rapid diagnostic tests (RDTs) and PCR tests, and they were grouped according household and individual characteristics. The relationships between putative risk factors and infection were quantified by multilevel logistic regression models. Of the 3,189 household members analyzed, 33.6% had positive RDT results and/or PCR test results. RDT-detected infections were more prevalent in children; however, PCR-detected infections were similarly prevalent across age groups. Recent travel was rarely reported and not significantly associated with infection. Bed net coverage was low and net crowding was associated with increased risks of household infections. Infections were present year-round, and fluctuations in prevalence were not associated with rainfall. These findings indicate year-round, endemic transmission with moderate population immunity. This is in stark contrast to recent estimates in this area. Therefore, further investigations to design effective intervention approaches to address malaria in this rapidly changing region and other similar settings across the Horn of Africa are warranted.

    • Supplemental Materials (PDF 253 KB)

Author Notes

Address correspondence to Hannah Meredith, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, E6003, Baltimore, MD 21205. E-mail: hmeredi4@jhmi.edu

These authors contributed equally as co-first authors.

These authors contributed equally as co-senior authors.

Disclosure: Written informed consent was obtained from all participants. The study procedures were approved by the ethics review board of Moi University and Duke University. The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Financial support: This work was supported by the National Institutes of Allergy and Infectious Diseases of the National Institutes of Health (R21AI133013 to W. P. O.). A. W. is funded by a Career Award at the Scientific Interface by the Burroughs Wellcome Fund, and by the National Library of Medicine of the National Institutes of Health (DP2LM013102). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Authors’ addresses: Hannah R. Meredith and Amy Wesolowski, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, E-mails: hmeredi4@jhmi.edu and awesolowski@jhu.edu. Diana Menya, Department of Epidemiology and Medical Statistics, School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya, E-mail: dianamenya@gmail.com. Daniel Esimit, Gilchrist Lokoel, and Samuel Lokemer, Department of Health Services and Sanitation, Turkana County, Kenya, E-mails: esimitdaniel@gmail.com, lockhell80@gmail.com, and lokemer0999@gmail.com. Joseph Kipkoech and George Ambani, Academic Model Providing Access to Healthcare, Eldoret, Kenya, E-mails: josepheddykipkoech@gmail.com and georgeambani@gmail.com. Betsy Freedman, Steve M. Taylor, and Wendy Prudhomme-O’Meara, Division of Infectious Diseases, School of Medicine, Duke University, Durham, NC, E-mails: betsy.freedman@duke.edu, steve.taylor@duke.edu, and wendy.omeara@duke.edu. James Maragia, Lodwar County Referral Hospital, Turkana County, Kenya, E-mail: mjmaragia@gmail.com. Andrew A. Obala, School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya, E-mail: andrew.obala@gmail.com.

Save