MTSI

La schistosomose dans les zones de faible endémicité, une maladie trop négligée. Le cas de Schistosoma mansoni au Brésil

Ricardo PEREIRA IGREJA — 2024-04-29

Schistosomiasis in areas of low endemicity: an overly neglected disease. The example of Schistosoma mansoni in Brazil

Human schistosomiasis is a parasitic disease caused by an infection with trematodes of the genus Schistosoma. The disease mainly affects impoverished populations. Around 800 million people are exposed to the infection, which is a public health problem in the tropical and subtropical regions of Africa, Asia, the Caribbean and South America. In Brazil, Schistosoma mansoni is the only species that causes schistosomiasis and the disease is widely distributed. Conventional diagnosis of the disease is carried out by detecting eggs using parasitological methods, such as the Kato-Katz test. Schistosomiasis has been reported in all regions of Brazil and is characterized as endemic in seven states in the Northeast Region and two states in the Southeast Region. In 2015, 78,7% of all cases reported in Brazil occurred in the Northeast Region. It is estimated that 1,5 million people is infected with this disease in Brazil and more than 25 millions live in areas with a high risk of transmission. Despite the reduction in mortality and morbidity, schistosomiasis was responsible for 8,756 deaths between 2000 and 2011 and 2,517 deaths between 2015 and 2019 in Brazil and it remains an important public health problem. In the state of Rio de Janeiro, some areas have low endemicity or isolated foci of Schistosoma mansoni and the majority of infected individuals have mild infections. The last survey of the disease in the state of Rio de Janeiro was carried out between 2010 and 2015 in students aged 7 to 17.

Schistosomiasis was reported in 10 of the 21 municipalities studied. Of the 5,111 school children screened for S. mansoni infection, 46 (1,65%) were tested positive. Studies carried out in areas of low endemicity in Rio de Janeiro showed that among the 205 patients infected by S. mansoni in Sumidouro, around 84% were aged 14 or over and all, except one individual, had the intestinal form (91,2%) or hepato-intestinal (8,3%) of schistosomiasis. Another study carried out in Sumidouro showed that with tests based on patent Schistosoma egg infection determined by the Kato-Katz test, active infections were diagnosed in eight (8/108) individuals. The intensity of infection expressed by parasite loads ranged from 6 to 72 eggs per gram of feces/individual. The results showed DNA amplification in 32 of the 100 individuals tested by real-time PCR. All individuals with patent ovo infection showed positive DNA amplification. These studies showed that if we only analyzed school-age children using the Kato-Katz test, the majority of the infected population would never be diagnosed with S. mansoni infection. In situations of low endemicity, with low intensities of infection, with low severity in the population and in the most affected age groups, schistosomiasis requires a more sensitive diagnostic approach (e.g. screening by PCR rather than Kato test), otherwise many infected individuals will remain invisible to the healthcare system.

La schistosomose dans les zones de faible endémicité, une maladie trop négligée. Le cas de Schistosoma mansoni au Brésil

La schistosomose humaine est une maladie parasitaire causée par une infection par des trématode du genre Schistosoma. La maladie touche principalement les populations démunies. Environ 800 millions de personnes sont exposées au risque de contracter l’infection et il s’agit d’un problème de santé publique dans les régions tropicales et subtropicales d’Afrique, d’Asie, des Caraïbes et d’Amérique du Sud. Au Brésil, la schistosomose est largement répandue. On estime que 1,5 million de personnes en sont infectées et plus de 25 millions vivent dans des zones à haut risque de transmission. Dans l’État de Rio de Janeiro existent certaines zones présentant une faible endémicité ou des foyers isolés de Schistosoma mansoni. La plupart des individus infectés présentent des infections bénignes. Des études réalisées dans des zones de faible endémicité à Rio de Janeiro ont montré que si l’on analysait uniquement les enfants d’âge scolaire à l’aide du test de Kato-Katz, la majorité de la population infectée ne bénéficierait jamais de diagnostic d’infection à S. mansoni. Dans les situations de faible endémicité, avec de faibles intensités d’infection, avec une morbidité réduite dans la population et les tranches d’âge les plus touchées, la schistosomose nécessite une approche diagnostique plus sensible (par exemple, dépistage par PCR plutôt que test de Kato), sinon de nombreuses personnes infectées resteront indécelables par le système de santé.

Esquistossomose em áreas de baixa endemicidade, uma doença muito negligenciada. O exemplo de Schistosoma mansoni no Brasil

A esquistossomose humana é uma doença parasitária causada por uma infecção por vermes sanguíneos do gênero Schistosoma. A doença afeta principalmente populações empobrecidas. Cerca de 800 milhões de pessoas estão expostas à infecção, sendo um problema de saúde pública nas regiões tropicais e subtropicais de África, Ásia, Caribe e América do Sul. No Brasil, o Schistosoma mansoni é a única espécie causadora da esquistossomose e a doença é amplamente distribuída. O diagnóstico convencional da doença é realizado pela detecção dos ovos através de métodos parasitológicos, como o teste de Kato-Katz. A esquistossomose foi notificada em todas as regiões do Brasil, e é caracterizada como endêmica em sete estados da Região Nordeste e dois estados da Região Sudeste. Em 2015, 78,7% de todos os casos notificados no Brasil ocorreram na Região Nordeste. Estima-se que 1,5 milhão de pessoas estejam infectadas com esta doença no Brasil e mais de 25 milhões vivam em áreas com alto risco de transmissão. Apesar da redução da mortalidade e morbidade, a esquistossomose foi relatada em 8.756 mortes entre 2000 e 2011 e em 2.517 mortes entre 2015 e 2019 no Brasil e continua sendo um importante problema de saúde pública. No Estado do Rio de Janeiro, algumas áreas apresentam baixa endemicidade ou focos isolados de Schistosoma mansoni e a maioria dos indivíduos infectados apresenta infecções leves. O último levantamento da doença no Estado do Rio de Janeiro foi realizado entre 2010 e 2015 em estudantes de 7 a 17 anos. A esquistossomose foi relatada em 10 dos 21 municípios estudados. Das 5.111 crianças escolares triadas para infecção por S. mansoni, 46 (1,65%) testaram positivo. Estudos realizados em áreas de baixa endemicidade no Rio de Janeiro mostraram que dentre os 205 pacientes infectados por S. mansoni em Sumidouro, cerca de 84% tinham 14 anos ou mais e todos, exceto um indivíduo, tinham a forma intestinal (91,2%) ou hepato-intestinal (8,3%) da esquistossomose. Outro estudo realizado em Sumidouro, mostrou que testes baseados em infecção patente de ovo de Schistosoma determinada pelo teste de Kato-Katz, infecções ativas foram diagnosticadas em oito (8/108) indivíduos. A intensidade de infecção expressa pelas cargas parasitárias variou de 6 a 72 ovos por grama de fezes/indivíduo. Os resultados mostraram amplificação do DNA em 32 dos 100 indivíduos testados por PCR em tempo real. Todos os indivíduos com infecção ovo-patente apresentaram amplificação de DNA positiva. Tais estudos mostraram que se analisarmos apenas crianças em idade escolar pelo teste de Kato-Katz, a maioria da população infectada nunca seria diagnosticada com infecção pelo S. mansoni. Em situações de baixa endemicidade, com baixas intensidades de infecção, com baixa gravidade na população e nas faixas etárias mais afetadas, a esquistossomose requer uma abordagem diagnóstica mais sensível (por exemplo, triagem por PCR em vez do teste de Kato), caso contrário, muitos indivíduos infectados permanecerão invisíveis para o sistema de saúde.

Infection au virus Zika : transmission sexuelle et conséquences sur la prévention

Paul Henri CONSIGNY — 2024-04-02

Zika virus infection: sexual transmission and implications for prevention

Zika virus infection, most often responsible for a benign arboviral disease or an asymptomatic infection, rarely Guillain-Barré syndrome, can become problematic in pregnant women, due to a risk of fetal malformations, in particular microcephaly linked to its neurotropism. The most recent large-scale epidemic was observed throughout Latin America between 2015 and 2017, causing several hundred thousand cases. Transmission is predominantly vector-borne, but sexual transmission has been described, mainly among travelers, although it undoubtedly accounts for a significant proportion of transmission in epidemic areas. The aim of this review is to describe this sexual transmission, mainly through examples linked to this large-scale epidemic in Latin America, to describe the link with prolonged excretion of infectious viral particles in genital secretions, especially semen but also vaginal secretions, and to highlight possible preventive measures apart from vector transmission, in particular the need for pregnant women or women wishing to become pregnant to avoid visiting countries where circulation of Zika virus is described.

Infection au virus Zika : transmission sexuelle et conséquences sur la prévention

L’infection au virus Zika, responsable le plus souvent d’un tableau arboviral bénin ou d’une infection asymptomatique, peut devenir problématique chez les femmes enceintes, en raison d’un risque de malformations fœtales. La transmission est majoritairement vectorielle, mais une transmission sexuelle est décrite, principalement chez des voyageurs, même si elle représente sans doute une part significative de la transmission en zone épidémique. Cette revue vise à décrire cette transmission sexuelle au travers principalement des exemples liés à l’épidémie de grande ampleur survenue en 2016 en Amérique latine, à en décrire le lien avec l’excrétion prolongée de particules virales infectieuses dans les sécrétions génitales, et à mettre en exergue les mesures de prévention possibles en dehors de la transmission vectorielle.

Pseudo-folliculite de la barbe chez les élèves policiers à Dakar : aspects épidémio-cliniques et facteurs de risque associés

Birame SECK — 2024-04-18

Pseudofolliculitis barbae in police students in Dakar: epidemiological and clinical aspects, and associated risk factors

Background. Pseudofolliculitis barbae (PFB) is a chronic inflammatory skin disease favoured by shaving. It is particularly common among black Africans belonging to certain socio-professional categories who are obliged to shave. Its aesthetic and professional damage is very significant. However, very few data are available for this condition, especially in Sub-Saharan Africa.

Objective. To determine the epidemiological and clinical aspects, and the risk factors associated with the occurrence of PFB in Dakar.

Population and methods. This was a descriptive cross-sectional study conducted in March 2019, including 655 police students at the National Police Academy in Dakar, all of African descent and with curly hair, who were required to shave weekly and agreed to participate in this study. The diagnosis of PFB was clinically based. Data analysis was processed using Epi-info version 6.0 software. Pearson's chi-square test was used for bivariate analysis with a significance threshold of p < 0.05. The Odds Ratio, with its 95% confidence interval, was used to determine the risk factors.

Results. Among the 655 officers, 254 had PFB, with a prevalence of 38.8%. The prevalence of PFB was 43.7% in men (242 men out of 554) and 11.9% in women (12 women out of 101). The average age of patients with PFB was 26.80 years (± 2.59), ranging from 22 to 36 years. The age of onset of PFB was between 18 and 20 years for the majority (39.8%), with a mean age of onset of 22.2 years (± 3.6). PFB lesions were pruritic in 84.6% of cases, papular in 96.8%, and/or pustular in 60.2%. The submandibular region was the most affected site (69.8%). Complications were noted in 90.1% of cases in the form of post-inflammatory hyperpigmentation (87%) and keloid scars (3.1%). The risk factors associated with PFB were male sex (p<0.0001; OR=5.7; CI95% [3.07-10.75]), family history of PFB (p<0.0001; OR=5; CI95% [3.35-7.37]), keloid-prone skin (p<0.0001; OR=2.9; CI95% [1.63-4.96]), association with acne keloidalis nuchae (p<0.0001; OR=8.8; CI95% [5.55-14.08]), use of a single-blade razor (p<0.0001; OR=2.5; CI95% [1.69-3.70]), use of a fixed-head razor (p<0.0001; OR=1.8 CI95% [1.28-2.77]), shaving against the grain (p<0.0001; OR = 6.3; CI95%= [4.33-9.08]), non-use of shaving products (p = 0.009; OR = 1.5; CI95%= [1.06-2]) and waxing (p<0.004; OR=2.7; CI95% [1.33-5.77]). On the other hand, the use of clippers (p<0.0001; OR = 0.5 CI95% [0.33-0.65]), pre-shave products (p<0.0001; OR = 0.4 CI95% [0.29-0.61]) and the use of razors with movable heads (p<0.0009; OR = 0.2 CI95% [0.17-0.35]) were protective factors against PFB.

Conclusion. Our study confirms the high incidence of PFB in this population of black men of African descent. A genetic abnormality revealed by shaving must be evoked in the occurrence of PFB. Further genetic and immunohistochemical studies would be needed to support this hypothesis.

Pseudo-folliculite de la barbe chez les élèves policiers à Dakar : aspects épidémio-cliniques et facteurs de risque associés

Introduction. La pseudo-folliculite de la barbe (PFB) est une dermatose inflammatoire chronique, favorisée par le rasage et affectant essentiellement la barbe, mais aussi les autres zones du corps rasées (pubis, aisselles). Elle est particulièrement fréquente chez les Noirs africains, causant un important préjudice esthétique et professionnel. Cependant, il existe très peu de données disponibles pour cette affection, surtout en Afrique subsaharienne. Notre objectif était de déterminer les aspects épidémiologiques et cliniques, ainsi que les facteurs de risque associés à la survenue de la PFB à Dakar.

Population et méthode. Il s’agit d’une étude transversale descriptive à visée analytique, réalisée en mars 2019, portant sur 655 élèves policiers pensionnaires de l’école nationale de police de Dakar, tous d’ascendance africaine et porteurs de cheveux crépus soumis à une obligation de rasage hebdomadaire. Le diagnostic de PFB était clinique.

Résultats. Sur les 655 élèves policiers, 254 présentaient une PFB, soit une prévalence de 38,8 %. La prévalence de la PFB était de 43,7 % chez les hommes et de 11,9 % chez les femmes. L’âge moyen des élèves présentant la PFB était de 26,8 ans. L’âge de début de la PFB était compris entre 18 et 22 ans chez la majorité (53,9 %). Les lésions de PFB étaient prurigineuses dans 84,6 % des cas, à type de papules dans 96,8 % des cas et/ou de pustules dans 60,2 % des cas. La région sous-mandibulaire était le site le plus affecté (69,8 %). Des complications étaient notées dans 90,1 % des cas, surtout à type d’hyperpigmentation post-inflammatoire (87 %). Les facteurs de risque associés à la PFB étaient le sexe masculin, l’existence d’un antécédent familial de PFB, la peau à tendance chéloïdienne, l’association à une folliculite fibrosante de la nuque, l’utilisation de rasoirs à lame unique ou à tête fixe, le rasage à contre-sens du poil, le non-usage de produits de rasage et l’épilation à la cire.

Conclusion. Notre étude confirme la fréquence élevée de la PFB dans cette population d’hommes noirs d’ascendance africaine. Une anomalie génétique révélée par le rasage doit être évoquée dans la survenue de la PFB, nécessitant ainsi d’autres études sur le plan génétique et immunohistochimique.

Un savon pour lutter contre les schistosomoses : une intervention de terrain à reprendre ?

Jean-Loup REY — 2024-04-08

A soap to fight schistosomiasis: a field intervention worth considering?

An experiment was carried out in 1985-87 against schistosomiasis using products neutralizing the intermediate stages of schistosomes. In the laboratory, it had been shown that lauryl betaines, amphoteric substances, used for children's shampoos, quickly immobilized miracidiums and cercariae. Studies in Niger in field conditions with water laden with organic matter gave similar results. This surfactant can be incorporated into ordinary soaps at a dose of 5% without changing their characteristics. Betaine soaps were put on sale in ordinary commercial channels in Niger then in Côte d’Ivoire, in hyperendemic villages for Schistosoma haematobium. Betaines diffused without external intervention into the water used by populations for washing. The soaps were well accepted by these populations. However, after one year, the results in tested villages compared to control ones were unclear on the dynamics of urinary schistosomiasis in terms of prevalence and oviuria. Anti-schistosome treatment seems necessary at the start of the procedure. The use of soap by populations needed to be measured. In conclusion, this promising laboratory action deserves to be evaluated again in the field, in addition to health education and systematic treatment actions.

Un savon pour lutter contre les schistosomoses : une intervention de terrain à reprendre ?

Une expérience a été menée en 1985-87 contre les schistosomoses par l’utilisation de produits neutralisant les stades intermédiaires des schistosomes. Au laboratoire, il avait été montré que les lauryl-bétaïnes, substances amphotères, utilisées pour les shampoings pour enfants, immobilisaient rapidement miracidiums et cercaires. Des études au Niger dans les conditions de terrain avec des eaux chargées en matières organiques ont donné des résultats similaires. Cet agent de surface peut être incorporé dans des savons ordinaires à la dose de 5 % sans modifier leurs caractéristiques. Des savons bétaïnés ont été mis en vente dans les circuits commerciaux ordinaires au Niger puis en Côte d’Ivoire, dans des villages hyperendémiques pour Schistosoma haematobium. Les bétaïnes ont diffusé dans les eaux utilisées par les populations pour se laver sans intervention extérieure. Ces savons ont été bien acceptés par ces populations. Après un an, le résultat par rapport à des villages témoins est mitigé sur la dynamique de la schistosomose urinaire en termes de prévalence et d’oviurie. Un traitement anti-schistosomes semble nécessaire au début de l’intervention. L’utilisation des savons par les populations est à mesurer. En conclusion, cette action prometteuse en laboratoire mériterait d’être à nouveau évaluée sur le terrain, en complément des actions de sensibilisation et de traitement systématique.