Prevalence, Sensitization and Intestinal Parasitic Infestation of Vernal Keratoconjunctivitis in Schoolchildren of Kinshasa, the Democratic Republic of the Congo

Background: The World Health Organizations (WHO) considered the allergic disease as the 4th disease in the world after cancer, cardiovascular pathologies and Acquis Immunosufficiency Disease Syndrome. Keratoconjunctivitis is also an area of concern across the globe as the vernal keratoconjunctivitis prevalence in Western Europe varies between 0.02% and 2.7% depending on the country in the year 2008. There is no study that estimates the prevalence of vernal keratoconjunctivitis and the association between vernal keratoconjunctivis and intestinal parasitic infestation in our setting. This study aimed to estimate the vernal keratoconjunctivitis prevalence, to describe the profile of sensitization and to determine the association between vernal keratoconjunctivitis disease and intestinal parasitic infestation in school children of Kinshasa during the scholar year from 2022 to 2023.
Methods: An observational, cross-sectional study was performed from September 2022 to June 2023. The children with vernal keratoconjunctivitis were recruited by using the four-stage probability sampling technique. Children attending in the school children of Kinshasa with vernal keratoconjunctivitis were enrolled in the classroom and underwent a clinical examination and skin prick test for 11 allergens and stool examination direct with microscope in the Laboratory. Data was entered in Microsoft Sheets using SPSS version 20.0. The Chi-square test was used to compare the sex, age groups, home environmental (grow trees and/or flowers around the yard), dampness in the house, keeping pets (cat and/or dog), number of people per household, number of people sharing a bedroom and intestinal parasitic infestation. The significant level was set to a value of p<0.05
Results: A total of 28800 students from four-stage probabilist sampling technique in school of Kinshasa were included, and 2100 students had symptoms according to the vernal keratoconjunctivitis related symptom questionnaire. Children with vernal keratoconjunctivitis were enrolled and the mean age ± standard was 7.2± 3.7 years, with a prevalence of 7.2 % and gender was three boys for one girl.
All vernal keratoconjunctivitis children recruited in urban and rural part had 33.1% positive skin prick test (SPT) and 67.9 % showed polysensitization. Children an urban part was more sensitized than rural respectively with Dermatophagoides pteronyssinus 28.1 %vs 28.9, p=0.00001, Blomia tropicalis
15.9 % vs 14.9 %, p=0.00001 and cockroach 12%vs 13%, p=0.00001 in both parts. The result revealed that the Children with vernal keratoconjunctivitis in urban part were more sensitized than children in the rural. Vernal keratoconjunctivitis children in rural part was more affected to intestinal parasite than urban with Ascaris lumbricoides 14 % vs 18.3 %, p=0.0006, followed by Ankylostome duodenalis 9.5 % vs 12.5 %, p=0.003, Anguillule 7.9 % vs 10.1 %, p= 0.001, Oxyure 5.7 %vs 8.2%, p=0.0001 and Trichirius trichiura2.6 % vs 3.3 %, p=0.0009.
Conclusion: This study outlines that the prevalence of vernal keratoconjunctivitis was 7.2 % and 33.1 % of children attending for vernal keratoconjunctivitis in school children had a positive skin prick test to at least one allergen, in particular for Dermatophagoides pteronyssinus, Blomia tropicalis and cockroach. The most common intestinal parasitic infestation was Ascaris lumbricoides, Ankylostome duodenalis, Anguillule and Trichirius trichiura. Henceforth, vernal keratoconjunctivitis is a significant health issue in Africa, especially in school-aged children that needs to managed effectively.