Davis Njuguna Karanja

Dr. Davis Njuguna Karanja


Research Focus & Metrics

Academic Career Length

1Year (2026-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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CTCHEROTICH JESCA Tangus
CHEROTICH JESCA Tangus
NMNdichu Maingi
Ndichu Maingi
JNJames Chege Nganga
James Chege Nganga
DKDavis Njuguna Karanja
Davis Njuguna Karanja
KNKariuki Njaanake
Kariuki Njaanake
BBBassirou Bonfoh
Bassirou Bonfoh
Toxoplasmosis is a widely distributed zoonosis caused by the protozoan parasite Toxoplasma gondii. Infection during pregnancy is a major public health concern due to its potential impact on both maternal health and fetal development. Early detection of maternal infection is critical to prevent adverse outcomes; however, maternal signs are often subtle, non-specific or absent, complicating timely diagnosis. This scoping review aimed to map and synthesise existing evidence on early maternal signs, pregnancy and foetal outcomes, frequently assessed risk factors, and diagnostic approaches of toxoplasmosis in expectant mothers in Africa. The review was done in accordance with the PRISMA-ScR guidelines. A literature search of PubMed, Scopus, ResearchGate, and Google Scholar was performed to identify studies published between 2000 and 2025. Retrieved records were managed using Zotero (version 8.0.4) for deduplication and screening. Only English-language studies conducted in Africa and reporting relevant maternal or clinical data were included. A total of 28 cross-sectional studies were included. Lymphadenopathy (25.0%) was the most frequently reported maternal early sign, followed by flu-like illness, asymptomatic infection, low-grade or mild fever, and fatigue or malaise (each 10.7%). Congenital anomalies (50.0%) and miscarriage or spontaneous abortion (42.9%) were the most commonly reported foetal and pregnancy outcomes. Frequently reported risk factors were exposure to cat faeces (57.1%) and ingestion of undercooked or raw meat (42.9%). Diagnostic approaches were commonly enzyme-based immunoassays (78.6%), with limited use of RDTs and molecular methods. These findings suggest the need for improved early detection and prevention strategies in high-risk, low-resource African settings. Enhancing routine screening, health education, and access to appropriate diagnostics are considered. Future studies should consider adopting standardised reporting and integrating sensitive, affordable, rapid diagnostic approaches to enhance early detection and reduce the burden of congenital toxoplasmosis.

Verified
Journal Article
Open access
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HMHellen Njeri Maingi
Hellen Njeri Maingi
MNMaingi Ndichu
Maingi Ndichu
JCJames Ng’Ang’A Chege
James Ng’Ang’A Chege
DKDavis Njuguna Karanja
Davis Njuguna Karanja
DSDerrick Noah Sentamu
Derrick Noah Sentamu
BBBassirou Bonfoh
Bassirou Bonfoh
Leishmaniasis is an endemic zoonotic disease caused by the protozoan parasite Leishmania and transmitted by infected female phlebotomine sandflies. The World Health Organization (WHO) classifies it among the 20 neglected tropical diseases (NTDs), ranking eighth globally. The disease predominantly affects resource-limited populations in tropical regions. Kenya bears a significant global burden of leishmaniasis, with Baringo County identified as a major endemic area. A cross-sectional survey on knowledge, attitudes, and practices (KAP) was conducted from July 2025 to January 2026 among 135 residents of Baringo South Sub-County using a structured questionnaire. The study evaluated sociodemographic characteristics, disease awareness, perceptions, preventive practices, and treatment-seeking behaviors. Additionally, 12 healthcare professionals were interviewed regarding their diagnostic and treatment capacities. Associations between variables were analyzed using Chi-square tests and multivariate logistic regression. Overall awareness of leishmaniasis was high (94.8%), with KAP scores of 86.7%, 76%, and 77.7%, respectively. Despite this, critical knowledge gaps persisted regarding transmission dynamics, the role of dogs as reservoir hosts, and preventive measures. Significant associations were found for awareness of local cases, recognition of clinical signs, knowledge of vector activity, community control measures, and attitudes toward treatment preferences. Age and education level predicted KAP outcomes. Healthcare practitioners demonstrated technical capacity to diagnose and treat human Leishmania infections, whereas veterinarians lacked awareness of Leishmania infection in dogs, including its diagnosis and treatment. Integration of human, animal, and vector surveillance within a One Health framework is recommended to enhance disease monitoring and control in Baringo County.

26 January 2026 in Preprints.org
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CTCHEROTICH JESCA Tangus
CHEROTICH JESCA Tangus
NMNdichu Maingi
Ndichu Maingi
JNJames Chege Nganga
James Chege Nganga
DKDavis Njuguna Karanja
Davis Njuguna Karanja
KNKariuki Njaanake
Kariuki Njaanake
BBBassirou Bonfoh
Bassirou Bonfoh
Toxoplasma gondii causes toxoplasmosis, a zoonosis of global importance, seriously affecting foetuses congenitally infected by their mother. Although early detection is important to prevent adverse fetal outcomes, maternal infections are frequently asymptomatic or present with mild, nonspecific signs. The present systematic review sought to synthesize evidence on early signs, risk factors, and diagnosis of toxoplasmosis in pregnant women. The study was conducted following the PRISMA 2020 guidelines. A literature search was conducted across PubMed, Scopus, ResearchGate, and Google Scholar for studies published between 2000 and 2025. The articles were exported to Zotero, citation management software. Duplicate articles were merged; those not published in English and lacking reference materials were excluded. After secondary screenings, 31 out of 407 articles met the inclusion criteria. Major maternal signs were lymphadenopathy (19.4%) and flu-like symptoms (19.4%), while major foetal effects were congenital anomalies (25.8%) and miscarriage (22.6%). Associated risk factors were contact with cat faeces and contaminated soil, consumption of undercooked or raw meat, raw vegetables, and contaminated water. Diagnosis was mainly by ELISA (65.5%). Therefore, routine screening awareness campaigns and timely diagnosis are recommended to safeguard maternal and fetal health in high-risk regions with limited diagnostic resources.

7 May 2026 in Preprints.org
Verified
Preprint
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HMHellen Njeri Maingi
Hellen Njeri Maingi
MNMaingi Ndichu
Maingi Ndichu
JCJames Ng’Ang’A Chege
James Ng’Ang’A Chege
DKDavis Njuguna Karanja
Davis Njuguna Karanja
DSDerrick Noah Sentamu
Derrick Noah Sentamu
BBBassirou Bonfoh
Bassirou Bonfoh
Leishmaniasis is an endemic zoonotic disease caused by protozoan parasite Leishmania and transmitted through bites of infected female phlebotomine sandflies. It is listed by the World Health Organization (WHO) as one of the 20 neglected tropical diseases (NTDs), ranking ninth globally. The disease affects resource-poor populations in tropical regions. Kenya is one of the endemic countries with the highest global burden of leishmaniasis with Baringo County being a major endemic focus. A cross-sectional KAP survey was conducted between July 2025 and January 2026 among 135 residents of Baringo South Sub-County using a structured questionnaire. The study assessed sociodemographic characteristics, awareness of the disease, perception, preventive practices. The perception of the residents on treatment-seeking behaviors was evaluated regarding leishmaniasis in Baringo County. About 12 healthcare professionals were also interviewed regarding their diagnostic and treatment capacity of healthcare provision in the region. Associations between variables were examined using multivariate logistic regressions. The overall awareness of leishmaniasis was high (94.8%) with Knowledge, attitudes, and practices scores as 86.7%, 76%, and 77.7% respectively. However, critical knowledge gaps on transmission dynamics, the role of role of dogs as reservoir hosts and preventive practices remained incomplete. Significant associations were observed for awareness of local cases, recognition of clinical signs, knowledge of vector activity, community control measures and attitude towards treatment preferences. Age and education levels were predictors of KAP. Health care practitioners demonstrated technical diagnostic and treatment capacity of human Leishmania infections while the veterinarians were not aware of the leishmania infection in dogs and its diagnoses and treatment. Therefore, the integration of human, animal, and vector surveillance within a One Health framework is essential to strengthen disease monitoring and control.

30 September 2026 in Pathogens
Verified
Journal Article
Open access
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HMHellen Njeri Maingi
Hellen Njeri Maingi
JCJames Ng’Ang’A Chege
James Ng’Ang’A Chege
RYRichard Brou Yapi
Richard Brou Yapi
DKDavis Njuguna Karanja
Davis Njuguna Karanja
MNMaingi Ndichu
Maingi Ndichu
BBBassirou Bonfoh
Bassirou Bonfoh
Background: Leishmaniasis is a vector-borne neglected tropical disease caused by obligate intracellular protozoan parasites of the genus Leishmania and transmitted by bites from infected female phlebotomine sand flies. Visceral leishmaniasis (VL), the most severe clinical form, remains a major public health concern in Eastern Africa and a priority for control and elimination. Although Baringo County is a well-established endemic focus in Kenya, the spatial distribution of human exposure and the socio-environmental determinants of infection remain inadequately characterized. This hospital-based cross-sectional study therefore estimated Leishmania seroprevalence. It assessed the sociodemographic, behavioral, and environmental predictors of seropositivity among patients presenting with clinical features suggestive of VL in two endemic sub-counties of Baringo County. Methods: A hospital-based cross-sectional study was conducted from January to March 2026 at Marigat and Chemolingot Sub-County Hospitals. We enrolled 260 patients with clinical features suggestive of VL through systematic sampling and tested them using the rK39 rapid diagnostic test (RDT) and an indirect enzyme-linked immunosorbent assay (ELISA). We collected sociodemographic, behavioral, household, and environmental data using a structured questionnaire. Associations between explanatory variables and ELISA seropositivity were evaluated using Pearson’s chi-square test or Fisher’s exact test. We included variables with p < 0.25 in multivariable logistic regression to identify independent predictors of seropositivity. Agreement between the rK39 RDT and ELISA was assessed using Cohen’s kappa statistics. We confirmed classical positive cases using bone marrow aspirates. Results: Overall Leishmania seroprevalence was 18.5% (95% CI: 14.2–23.7) by rK39 RDT and 20.8% (95% CI: 16.2–26.2) by ELISA. ELISA seroprevalence was substantially higher in Tiaty Sub-County (36.6%) than in Baringo South Sub-County (4.7%). Residence in Tiaty was independently associated with markedly higher odds of seropositivity than residence in Baringo South [aOR] = 11.30, 95% CI: 1.96–64.97; p = 0.007. Compared with children aged < 15 years, participants aged 15–44 years had lower odds of seropositivity (aOR = 0.30, 95% CI: 0.11–0.93; p = 0.037). Residents without a dog had higher odds of seropositivity (aOR = 3.17, 95% CI: 1.06–9.50; p = 0.039) than those with a dog. After adjustment, no other predicted factors were independently associated with seropositivity, suggesting that geographical differences may have confounded the unadjusted associations. Conclusion: Leishmania seroprevalence was substantial and unevenly distributed, with Tiaty Sub-County and children under 15 years bearing the greatest burden. Therefore, targeted, child-focused surveillance and integrated One Health interventions, including early case detection, improved housing, personal protection, vector-habitat management, and community education, are needed to strengthen VL control and advance the WHO 2030 targets for the Neglected Tropical Diseases Roadmap 2021–2030.

14 July 2026 in Preprints.org
Verified
Preprint
Open access
PDF file
CTCHEROTICH JESCA Tangus
CHEROTICH JESCA Tangus
LBLOKONON Bruno
LOKONON Bruno
NMNdichu Maingi
Ndichu Maingi
JNJames Chege Nganga
James Chege Nganga
DKDavis Njuguna Karanja
Davis Njuguna Karanja
BBBassirou Bonfoh
Bassirou Bonfoh
Background: Toxoplasma gondii infection during pregnancy may lead to congenital toxoplasmosis and serious pregnancy complications. In Kenya, however, toxoplasmosis is not screened during routine antenatal care, and there is limited local data on maternal seroprevalence and associated risk factors. This study determined the seroprevalence of T. gondii infection and examined its association with socio-demographic characteristics, awareness levels, and exposure behaviours among pregnant women visiting the antenatal clinic at Pumwani Maternity Hospital in Nairobi, Kenya. Methods: A cross-sectional study was conducted among 298 pregnant women consecutively recruited at Pumwani Maternity Hospital in Nairobi County between July and October 2025. Data on socio-demographic characteristics, knowledge, and exposure practices were collected using a pre-tested structured questionnaire. Blood specimens were obtained from consenting prenatal patients, and anti-T. gondii IgG antibodies were detected by indirect enzyme-linked immunosorbent assay (ELISA). Associations between seropositivity and risk factors were assessed using Pearson's chi-square or Fisher's exact tests, followed by multivariable logistic regression. Results: The overall anti-T. gondii IgG seroprevalence was 24.5% (73/298). In the adjusted analysis, unemployment (AOR = 2.95, 95% CI: 1.25–7.22; p = 0.02) and parity ≥4 (AOR = 3.25, 95% CI: 1.27–8.39; p = 0.01) were independently associated with seropositivity. Awareness of risk groups was associated with seropositivity in the univariable analysis but not independently after adjustment. Stratified analyses identified significant demographic differences in exposure practices, including consumption of undercooked meat in the third trimester of pregnancy (p = 0.021) and consumption of unwashed vegetables by pregnant women from Kamkunji Sub-County (p = 0.005). Parity of three (p = 0.007) increased the risk of infection. Conclusions: Approximately one-quarter (24.5%) of pregnant women showed evidence of exposure to T. gondii. Socioeconomic predictors, including unemployment, and obstetric history (parity ≥4) were independently associated with seropositivity, whereas awareness of risk groups showed only a univariable association that didn't persist after adjustment for confounders. Behavioural exposures varied across trimesters and regions, signalling a need for integrated antenatal education and food safety steps within a One Health framework. The results support integrating maternal health, food safety, and environmental health programs into Kenya's antenatal care to reduce the risk of congenital toxoplasmosis through a comprehensive One Health approach.