CDC Kenya Science

In Kenya, malaria remains a leading cause of illness and death. Since 1979, CDC has collaborated on malaria research projects in western Kenya, which harbors the largest burden of disease in the country. In 2018, CDC Kenya’s malaria research program made headway in evaluating new prevention and treatment tools in the fight against malaria.

New study shows drug that kills mosquitoes could be used to fight malaria
One of these studies has shown the potential impact of a new drug strategy for breaking the transmission cycle of malaria. The study showed that when a mosquito bites a person who has taken ivermectin, an anti-parasitic drug, within the last 28 days, that the mosquito dies, thus breaking the malaria transmission cycle. This differs from existing drugs that target the parasite to reduce the spread of malaria.

For this study a team of scientists from CDC Kenya, KEMRI, the Liverpool School of Tropical Medicine (LSTM), and other organizations, carried out a randomized controlled trial. The results were published in June 2018 in Lancet Infectious Diseases, and show that adding high doses of ivermectin to the antimalarial dihydroartemisinin-piperaquine (DP) has a major and prolonged effect on mosquito mortality.

“This first evaluation of the impact of high dose ivermectin on mosquito mortality is highly encouraging and requires further evaluation in larger scale trials that target both malaria parasites and the mosquitos, as the world pushes towards malaria elimination”, explained LSTM’s Professor Feiko ter Kuile, senior author of the paper.

Ramping up disease surveillance

Disease surveillance systems are the backbone of all public health systems providing the data necessary to monitor trends, show the impact of interventions, estimate testing and treatment commodity needs, and identify and respond to outbreaks. Malaria surveillance poses a specific challenge; the majority of cases of malaria in western Kenya do not result in disease, and therefore case counts at health facilities substantially underestimate the burden in the community. Cross-sectional studies, which have traditionally been the gold-standard, are not sustainable due to their expense.

Understanding this, CDC invested resources over the last 3 years to investigate both new systems and novel ways for using existing systems to monitor malaria in the community. The first step was creating a continuous malaria indicator survey (cMIS) that is used for collecting data every working day of the year. This system provides the gold-standard for testing whether other approaches can accurately detect real-time trends in malaria infection. Next, the team focused on evaluating more sustainable methods for performing malaria surveillance. One such method determines whether positive malaria tests in pregnant women attending their first antenatal care (ANC) clinic visit accurately estimate malaria infection prevalence in the community. After 2.5 years of data collection, analyses demonstrates that women attending first ANC clinic visits show a strong correlation with community infection prevalence and may supplement existing surveillance systems. Initial study results were presented at the 2018 American Society of Tropical Medicine and Hygiene Annual Conference in New Orleans. Based upon this cutting-edge work in Kenya, the President’s Malaria Initiative is performing pilot evaluations in four other sub-Saharan African countries.

The CDC team’s next challenge is to evaluate use of this system to identify hotspots of malaria disease, and direct the appropriate response for targeted interventions. This important work has begun in earnest and will be the focus of the CDC Kenya’s malaria surveillance studies for 2019 and 2020.

Young women and adolescent girls remain at high risk for HIV, and prevention methods that are both acceptable and accessible to them are critical to their well-being. Over the past 10 years, public health officials and researchers have made progress in preventing new HIV infections through the use of innovative methods. Additionally, many women are seeking contraception to prevent pregnancy. New research is looking at combined methods that offer dual protection from both HIV and pregnancy.

The Western Kenya Clinical Research site, a collaboration between CDC Kenya and KEMRI, has been conducting high-quality clinical research studies for more than a decade and in recent years has contributed data to more than a dozen multisite international HIV and TB clinical trials.

Two important studies sponsored by the National Institutes of Health (NIH)’s HIV Prevention Trials Network (HPTN) are currently underway, one of which has already reached its target enrollment of participants: the Antibody Mediated Prevention (AMP) study which looks at the effectiveness of a monoclonal antibody for the prevention of HIV; and the Long-acting Injectable For the Epidemic (LIFE) study which evaluates the safety and efficacy of an injectable antiretroviral, Cabotegravir, for HIV prevention in women.

Further plans are underway to launch two more studies that will use an intravaginal ring to prevent HIV in women. The recent study includes a ring that contains both an agent to prevent HIV infection and a hormonal contraceptive. Additionally, the NIH’s Microbicide Trials Network’s REACH (Reversing the Epidemic in Africa with Choices in Prevention) study will compare adherence to an intravaginal ring that has an antiretroviral drug and daily oral pre-exposure prophylaxis targeting women between the ages of 16-21 years.

These studies will help protect and empower adolescent girls and young women in Kenya and around the world from getting HIV.

Next Generation Sequencing (NGS), a technology that allows DNA and RNA to be sequenced much more quickly and cheaply, is rapidly changing the practice of microbiology. NGS capacity in public health laboratories is one of the most important advances in diagnosing infectious diseases over the last three decades because it gives each pathogen a unique fingerprint.

In 2018, CDC established NGS capacity in Kenya to detect bacterial pathogens. The teams involved worked concurrently in two of CDC’s Global Disease Detection sites in Kenya and Thailand to develop this advanced capacity, provide training, and supply the required NGS equipment. Initial implementation included sequencing of Salmonella bacterial isolates to highlight the resistance patterns to commonly used antibiotics. The process tracks circulating bacteria in time and space, providing data which can be used to prevent spread and thus reduce disease in the Kenyan population.

Every year, Kenya experiences disease outbreaks from various pathogens. Often, health experts are unable to determine which disease is causing the outbreak. Incorporating NGS technology in the diagnostic capacity now allows CDC to sequence an entire pathogen genome to identify whether the pathogen is viral or bacterial, characterize its antimicrobial resistance, determine factors that increase the pathogen’s ability to cause severe disease as well as its typing and molecular epidemiology in the public health laboratory. This advanced technology, however, can be difficult to implement without the appropriate laboratory infrastructure and human resources.

Implementing NGS in Kenya has enabled laboratorians to become self-sufficient and problem-solve issues without external expertise. Once programs implement sequencing as a routine diagnostic technique for one enteric bacterial pathogen, the same methods may be applied for other bacterial pathogens. Scientists hope that this approach will set the stage for progression towards more complex NGS procedures including testing of a broader range of specimens, and increase capacity for detecting novel pathogens.

Expectant mothers are among those most at risk of developing serious complications from influenza (flu). When a woman becomes pregnant, changes to her immune system, heart, and lungs make her more prone to severe illness from flu, including illness resulting in hospitalization.

In 2012, the World Health Organization (WHO) recommended that pregnant women should have the highest priority for seasonal flu vaccination in countries starting or expanding flu immunization programs. This is because flu vaccine has a long track record of safety when administered during pregnancy and is the best way to protect expectant mothers from the effects of flu. Moreover, when a pregnant woman is vaccinated, she produces protective antibodies against flu that are passed in-utero to her baby, protecting newborns from flu for the first several months of life. Infants younger than 6 months of age are too young to be vaccinated, but also are at high risk of serious flu complications, so the protection gained from their mother’s vaccination is very important.

To guide the Kenya government as it considers expanding its flu vaccination program to include pregnant women, CDC Kenya—in collaboration with the Kenya Medical Research Institute (KEMRI)—is leading a demonstration project to vaccinate pregnant women in Kenya’s Siaya County. The study aims to enroll more than 400 pregnant women, give them a flu vaccine and measure how well they develop immune protection after vaccination as well as measure the flu antibodies transferred in utero to the babies. The study includes vaccinating pregnant women who are HIV+ or who had malaria when vaccinated. The study began in June 2018 and has already enrolled more than 100 mothers. The study team relate that pregnant women participating in the project have had positive experiences, and many have encouraged other pregnant women to participate in the study.

Kenya has not yet adopted a flu vaccine recommendation for pregnant women, partly due to lack of local data to support such a policy. The current recommendation of the Kenya National Immunization Technical Advisory Group (KENITAG) focuses on children 6 to 23 months of age due to the high number of flu cases among very young children. KENITAG has also requested country-driven data on the impact of flu among pregnant women and their babies, emphasizing the need to understand if the flu vaccine would work as well in mothers who suffer from HIV or malaria, and if these mothers would transfer antibodies against flu to their babies.

CDC expects that findings from this study will inform decision-making by the Kenya Ministry of Health on the adoption of a flu vaccination policy for pregnant women. If adopted, this policy will serve as an important public health step in Kenya, and serve as an example to other countries in the region.