Integrated screening reveals rare co-infections of gambiense human African trypanosomiasis, malaria and loiasis in Banga, northern Angola

Gambiense human African trypanosomiasis (gHAT), malaria, and loiasis overlap geographically in Central Africa and share non-specific clinical features. As gHAT incidence declines, integrated screening in co-endemic settings must balance sensitivity, specificity, and programmatic efficiency. We conducted a retrospective cross-sectional analysis of data from an integrated active community screening program conducted between June and September 2021 in Banga municipality, Cuanza Norte Province, Angola. Demographic and diagnostic data for malaria (Plasmodium falciparum), gHAT (Trypanosoma brucei gambiense), and loiasis (Loa loa) were analysed. Malaria was diagnosed using rapid diagnostic tests; gHAT was screened serologically with parasitological confirmation; loiasis was detected incidentally during parasitological examinations. Prevalence estimates were stratified by sex, age group, and commune. Associations were assessed using chi-square or Fishers exact tests, and multivariable logistic regression was used to evaluate factors associated with malaria infection. Among 6,117 screened individuals, malaria was highly prevalent (62.9%), with substantial heterogeneity by age and commune. Prevalence was highest in children aged 5-14 years (>70%) and decreased progressively with increasing age. Male sex was independently associated with malaria infection (adjusted OR 1.39; 95% CI 1.26-1.53), as was commune of residence (p<0.001). gHAT and loiasis were detected at low frequency (<1% each). Most participants had either no infection (36.6%) or a single infection (63.0%), while co-infections were rare, occurring in 0.43% (26/6,117) of individuals. In this co-endemic setting, malaria remains the dominant infection, while gHAT and loiasis occur infrequently but retain high surveillance importance. Integrated screening platforms can efficiently support gHAT elimination in malaria-endemic areas, provided that robust confirmatory algorithms are maintained to manage diagnostic complexity and rare co-infections. AUTHOR SUMMARYHuman African trypanosomiasis (sleeping sickness), malaria, and loiasis occur in overlapping ecological settings in Central Africa and can affect the same communities. Although sleeping sickness is approaching elimination, malaria remains highly prevalent, and loiasis continues to pose challenges for diagnosis and treatment in co-endemic areas. Understanding how these infections occur together is important for designing efficient surveillance and care strategies. We analysed data from an integrated community screening campaign conducted in 2021 in Banga municipality, northern Angola. More than six thousand people were screened for malaria, sleeping sickness, and loiasis. Malaria was very common, especially among children, while sleeping sickness and loiasis were rare. Most individuals had either no infection or only one infection, and co-infections involving two or more parasites were uncommon. Our findings show that integrated screening can efficiently detect malaria while maintaining surveillance for sleeping sickness in areas close to elimination. However, even rare infections such as loiasis remain important because they can complicate diagnosis and clinical management. These results support the continued use of integrated approaches in endemic settings, combined with careful confirmatory testing, to improve patient care and sustain progress toward the elimination of sleeping sickness.