Mansonella ozzardi and its vectors in the New World: an update with emphasis on the current situation in Haiti.

Mansonella ozzardi (Nematoda: Onchocercidae) is a little studied filarial nematode. This human parasite, transmitted by two families of dipteran vectors, biting midges (most of them members of the genus Culicoides) and blackflies (genus Simulium), is endemic to the Neotropical regions of the New World. With a patchy geographical distribution from southern Mexico to north-western Argentina, human infection with M. ozzardi is highly prevalent in some of the Caribbean islands, along riverine communities in the Amazon Basin, and on both sides of the border between Bolivia and Argentina. Studies conducted in Haiti between 1974 and 1984 allowed the first complete description of the adult worm and permitted clarification of the taxonomic position of this filarial species. This paper reports the known geographical distribution of M. ozzardi in Neotropical regions of the Americas, and focuses on the current situation in Haiti where this filariasis remains a completely neglected public health problem.

Seroprevalence of human Taenia solium cysticercosis in Haiti.

Human Taenia solium cysticercosis is common in developing countries due to poor sanitary conditions and economics based on breeding livestock, especially pigs, with low hygiene standards. Neurocysticercosis, caused by migration of the larvae of the tapeworm in the nervous system, is the leading cause of acquired epilepsy in adults in Central and South America, sub-Saharan Africa, and East and South Asia. This makes neurocysticercosis a large public health problem in developing countries. Two clinical cases of neurocysticercosis have been observed recently in Haiti. In order to evaluate the prevalence of human T. solium cysticercosis in this country, in 2007 we conducted a cross-sectional serological retrospective survey using a Western blotting test (LDBIO Diagnostics) in Port-au-Prince, where sewage systems are rare and swine usually roam freely throughout the area. A total of 216 serum samples, obtained from healthy adults seen in the work setting of periodical medical visits, were tested after storage at - 20 degrees C. The frequency of antibodies in serum samples of the study population was 2.8% (6/216). The immunodominant bands recognized in Western blots were 23-26 kDa (100%), 39 kDa (67%), 45 kDa and 6-8 kDa (50%), 50-55 kDa (33%). These results confirm for the first time an endemic situation of cysticercosis in humans in Haiti, with similar prevalence as that reported in other Latin American and African countries. It reinforces the urgent need for control and prevention measures to be taken by local public health services.

[Simplified Protocols for Cholera Diagnosis in the National Public Health Laboratory, Port-au-Prince, Haiti]. / Protocoles simplifiés de diagnostic du choléra au Laboratoire national de santé publique, Port-au-Prince, Haïti.

While the incidence of cholera is decreasing in Haiti, the time required to render stool culture results with antibiogram using the standard method practiced at the National Public Health Laboratory (LNSP) remains at an average of 80 hours. This delay can be further lengthened by the process of rendering the analysis reports to the sites of care which significantly delays the community responses to cholera. Through this study, we have aimed to assess the reliability of partial results. We have studied 250 stool samples that were analyzed between January and September 2017 at the LNSP by determining the specificity, positive predictive value and positive likelihood ratio of i) the identification of yellowish colonies and ii) the identification of yellowish colonies with a positive oxidase assay in comparison to the stool culture. Compared to the entire process, the identification of yellowish colonies showed a specificity of 56%, a positive predictive value of 69% and a positive likelihood ratio of 2.27. The identification of yellowish colonies with a positive oxidase assay showed a specificity of 77%, a positive predictive value of 81% and a positive likelihood ratio of 4.31. The communication of partial results at these steps would likely guide community interventions despite a relative decrease in reliability of the results.

Le temps nécessaire au rendu des résultats de culture des selles avec antibiogramme par la méthode classique pratiquée au Laboratoire national de santé publique (LNSP) d'Haïti s'étale sur une durée de 80 heures en moyenne. Ce délai peut être encore allongé par le processus de rendu des rapports d'analyse aux sites de prise en charge, ce qui retarde de manière significative les réponses communautaires face au choléra. Cette étude vise à évaluer la fiabilité de résultats partiels par rapport au processus complet. Nous avons inclus 250 échantillons de selles analysés au LNSP de janvier à septembre 2017 en déterminant la spécificité, la valeur prédictive positive et le rapport de vraisemblance positif de l'identification des colonies jaunâtres et de l'identification des colonies jaunâtres oxydase positive. Par rapport au processus complet de culture des selles, l'identification des colonies jaunâtres a montré une spécificité de 56 %, une valeur prédictive positive de 69 % et un rapport de vraisemblance positif de 2,27. Quant à l'identification des colonies jaunâtres oxydase positive, la spécificité est de 77 %, la valeur prédictive positive de 81 % et le rapport de vraisemblance positif de 4,31. La communication de résultats partiels aux équipes de terrain à ces étapes serait utile pour guider les interventions en dépit d'une relative diminution de leur fiabilité par rapport au gold standard.

[Update of knowledge on Neglected Diseases in Haiti: Mansonelliasis, Tungiasis, Leprosy, and Anthrax]. / Mise à jour des connaissances concernant quatre maladies délaissées en Haïti : mansonellose, tungose, lèpre, charbon.

Haiti, like most limited-resources countries in the world, faces numerous neglected infectious diseases. They represent a real public health issue with lethal consequences especially in children. We are reviewing here the available literature on four neglected infectious diseases, mansonelliasis, tungiasis, leprosy and anthrax. Filariasis, due to Mansonella ozzardi, has been totally neglected since its discovery in 1920 in Haiti; it persists in coastal homes with a high prevalence in adults when an effective treatment is available. The skin lesions caused by Tunga penetrans have existed since the pre-Columbian period in Haiti. They persist in the most retreated and hard-to-reach areas where the population lives in precarious conditions and in extreme poverty. New available research data show the importance of the problem with very high prevalence rates in some rural communities far away from any healthcare center. Cases of leprosy are recently reemerging as no monitoring program has been in place since 2004. Finally, anthrax is still endemic; small epidemics resurfacing periodically in families in rural areas. Screening of people for these diseases and managing the cases are necessary to improve health and reduce morbidity and mortality in Haiti.

Comme dans la plupart des pays pauvres de la planète, les maladies infectieuses négligées sont nombreuses en Haïti où elles représentent un réel problème de santé publique avec des conséquences létales, surtout pour les enfants. Nous faisons le point des données accessibles pour quatre d'entre elles. Totalement délaissée depuis la découverte de sa présence en Haïti en 1920, la filariose due à Mansonella ozzardi persiste en foyers côtiers avec une prévalence élevée chez les adultes alors qu'un traitement efficace est disponible. Connues depuis la période précolombienne dans l'île d'Hispaniola, les lésions cutanées dues à Tunga penetrans persistent dans les régions les plus reculées et difficiles d'accès où la population vit dans des conditions précaires et dans une très grande pauvreté. Nous rapportons les données d'enquêtes récentes qui montrent l'importance de cette ectoparasitose en Haïti où les taux de prévalence sont très élevés dans certaines communautés rurales isolées. Des cas de lèpre resurgissent en Haïti alors qu'aucun programme de surveillance n'est effectif depuis 2004. Enfin, la maladie du charbon est endémique dans les régions d'élevage où des épidémies familiales resurgissent périodiquement en milieu rural. Le dépistage des personnes atteintes de ces maladies et leur prise en charge sont nécessaires pour une amélioration de la santé et une baisse de la mortalité en Haïti.

[Hepatobiliary fascioliasis and echinococcosis/hydatidosis in domestic animals in Haiti]. / Distomatose hépatobiliaire et échinococcose- hydatidose des animaux domestiques en Haïti.

In Haiti, hepatobiliary fascioliasis and hepatic hydatid cysts cause major economic losses among livestock. Surveys show high prevalence rates for bovine distomatosis caused by Fasciola hepatica (10.7% to 22.78%). Among small ruminants, the prevalence of distomatosis is low (sheep: 3.2%, goats: 0.9%) although Dicrocoelium dendriticum is found in 1.1% of sheep. Hepatic hydatidosis is more common among pigs (5.2%) and sheep (2.1%) than among goats (0.9%) and cattle (0.3%). In the case of dogs, 21% excrete egg-bearing segments in their faeces and 25% harbour Echinococcus granulosus in the small intestine. As a result of local dietary habits (consumption of raw cress), environmental pollution by animal faeces, poverty and poor standards of hygiene in Haiti, these flatworms pose serious health risks to the population, even though this is largely unknown at present.

[Worldwide human zoonotic cryptosporidiosis caused by Cryptosporidium felis]. / La cryptosporidiose zoonosique humaine due à Cryptosporidium felis dans le monde.

Cryptosporidium is an important enteric pathogen worldwide distributed causing diarrhoeal illness in humans and animals. Identifying Cryptosporidium species using conventional criteria, such as oocyst morphology, is inadequate. The advent of molecular techniques has conducted to characterize different species and genotypes of Cryptosporidium infecting humans. The vast majority of human cases of cryptosporidiosis in the world are caused by both species, Cryptosporidium hominis and Cryptosporidium parvum. However other species including Cryptosporidium felis can infect humans too. In this review, we analyse 58 reported cases of human C. felis infection in different parts of the world. To date this emerging protozoan disease is present in humans around the world, except in Australia and Oceania. Adults and children are infected, more often when immunocompromised by HIV infection (83 % of reported cases). Apparently immunocompetent individuals are also infected by C. felis. In developing countries, inhabitants are more likely infected by C. felis probably through the oocyst contamination of drinking or recreational water. The public health importance of C. felis infection in tropical countries remains to be evaluated.

[Bilharziasis caused by Schistosoma mansoni in a traveler returning from Guinea: failure of serodiagnostic testing]. / Bilharziose à Schistosoma mansoniau retour de Guinée: défaillance du sérodiagnostic.

The purpose of this report is to describe a case of febrile hypereosinophilic syndrome in a traveler three weeks after returning from a sightseeing trip to Guinea. Laboratory testing demonstrated an inflammatory response syndrome and hepatic cytolysis. Parasite serology led to suspicion of toxocariasis that was treated using albendazole. Follow-up tests at two months showed the presence of Schistosoma mansoni eggs in stools despite negative standard serodiagnostic testing (hemagglutination). Secondarily Western blot testing of serum samples at one, two and 14 months after returning from Guinea continued to show only protein bands specific to toxocariasis with no bands specific to bilhariziasis. These findings provide further evidence of the limitations of serological testing for detection of bilharziasis in travelers and the difficulty of diagnosis. Guinea is a high-risk tourist destination. Intestinal and urinary bilharziasis are endemic over three-fourths of country. Travelers planning even short stays in areas where bilharziasis is endemic should be advised on preventive measures.

[Enteric parasites and AIDS in Haiti: utility of detection and treatment of intestinal parasites in family members]. / Parasites intestinaux et sida en Haïti: faut-il déparasiter l'entourage familial?

Intestinal parasites and human immunodeficiency virus (HIV) are major health problems in Haiti. Both entities are known to interact strongly with cell-mediated immunity. The purpose of this study undertaken in Port-au-Prince, Haiti was to evaluate the risk of enteric parasite transmission between HIV-infected patients and family members. Routine examination of stool specimens for parasites was conducted in 90 HIV-infected undergoing treatment for intestinal disorders due mainly to Cryptosporidium sp. (62%) and 123 healthy family member volunteers. A stool sample preserved in 10% formalin solution was examined to detect protozoa (MIF, modified Ziehl-Neelsen stain, Uvibio fluorescence technique, Weber stain) and helminth ova (Bailenger technique). In addition to Cryptosporidium sp., 14 parasitic species were identified: 6 Rhizopoda, 3 Flagellata (including Giardia duodenalis), 1 Coccidia (Cyclospora cayetanensis), 3 Nematoda (mainly Ascaris lumbricoides) and 1 Cestoda (Hymenolepis nana). This is the first time that 5 protozoa, i.e., Blastocystis hominis, Entamoeba hartmanni, E. polecki, Chilomastix mesnili, and Enteromonas hominis, have been reported in Haiti. As expected, enteric parasites were less common in HIV-infected subjects undergoing medical treatment (11.1%) than in uninfected family members (41.5%) (p = 0.0000). Multiple intestinal parasitism (infection by 2 to 4 parasites) was observed in 19.5% of family members. The findings of this study indicate that detecting and treating intestinal parasites in subjects living in close contact with HIV-infected patients as well as informing family members of the importance of personal hygiene in Haiti are highly recommended measures to preserve the health of AIDS patients.

[Intestinal helminthiasis in school children in Haiti in 2002]. / Helminthoses intestinales en milieu scolaire en Haïti en 2002.

A survey on intestinal helminths in school children was conducted in Haiti in 2002. This first nationwide study involving the entire country was stratified by department according to urban and rural zones using the cluster method. Focusing on elementary school children (n=5792; age range 3 to 20 years), it involved 26 urban and 49 rural schools randomly selected. Stools were preserved in formalin and examined by the Ritchie technique. Thirty-four per cent of stools (1981/5792) tested positive for intestinal helminths with the following parasites identified: Ascaris lumbricoides (27.3%), Trichuris trichiura (7.3%), Necator americanus (3.8%), Hymenolepsis nana (2%), Taenia sp. (0.3%) and Strongyloides stercoralis (0.2%). The helminth prevalence was higher in rural (38.4%) compared to urban areas (30%). There was no significant difference in prevalence by sex and age. The importance of geohelminths changed from one department to another with the highest prevalence found in the Southern department of Grande Anse (73.7%) and the lowest prevalence in the Center department (20.6%). Five out of the country's nine departments had a similar prevalence varying from 25.5% to 28.2%. Intestinal helminthic polyparasitism was observed in a percentage of infested school children comprise between 3.4% and 28.6% according in relation to the geographical area. A program to fight against geohelminths in school children should be initiated as a public health priority. Albendazole is the drug of choice. Frequency of drug distribution should be based on the prevalence of geohelminths in each department.

[Changes in malaria prevalence and management of fevers from 2000 to 2012 in Casamance, Senegal]. / Évolution de la prévalence du paludisme et de la prise en charge des fièvres de 2000 et 2012 en Casamance, Sénégal.

Before 2006 in Senegal, in the absence of clinical diagnosis, all fever cases were considered as malaria and treated with chloroquine. Between 2004-2006, to face the dramatic increase of Plasmodium falciparum resistance to chloroquine, the combination of amodiaquine plus sulfadoxine-pyriméthamine was recommended for treatment. In 2006, rapid diagnostic tests were introduced and the treatment with a combination of artesunate plus amodiaquine (ASAQ) became the national recommendation for malaria treatment in 2007. This coincided with a decrease of the prevalence of malaria cases and change in fever management. Since 1995 in Mlomp in Casamance, thin and thick blood smear examination has systematically been done in patients with fever and clinical signs of malaria, and treatment with ASAQ given as experimental procedure. Between 2000 and 2012, 70,892 outpatients were attending the health center, and 51.2% of them for fever. Among these fever cases, 72.4% were suspected of malaria and 27.6% were identified as bacterial and viral infections. Confirmed malaria cases decreased dramatically from 1365 in 2000 to 53 in 2012. While comparing the 2 periods 2000-2006 and 2007-2012, the number of fever cases decreased by half, the number of fever identified as non malaria doubled and malaria treatment given decreased by 86%. Improvement of fever management in Mlomp has contributed to a better identification of their cause and to a decrease of inappropriate malaria treatments.

[Gametocyte carriage in asymptomatic Plasmodium falciparum infections in Haiti (2010-2013)]. / Portage de gamétocytes de Plasmodium falciparum en Haïti en 2010-2013.

A survey conducted from May 2010 to October 2013 in five from ten departments of Haiti among 5,342 persons aged from 1 to 107 years showed a gametocytic rate = 3.2%. However, it varies greatly from one Department to another, ranging from 0.5% in Grande Anse Department to 5.9% in Southeast Department. Malaria is present in Haiti in heterogeneous coastal foci. Gametocytes occur at all ages, but two times most often in male under 20 years. Entomological studies in Haiti are needed to better characterize the relationships between man and the vector Anopheles albimanus, adapting the fight more effectively.

Invasive infections due to Trichoderma species: report of 2 cases, findings of in vitro susceptibility testing, and review of the literature.

Trichoderma species are filamentous fungi that were previously considered to be culture contaminants. We report 2 well-documented cases of invasive Trichoderma infections, and we comprehensively review the literature on this topic. Trichoderma species are mainly responsible for continuous ambulatory peritoneal dialysis-associated peritonitis (7 cases) and invasive infections in immunocompromised patients (9 cases) with a hematologic malignancy or solid-organ transplant. Definitive diagnosis is difficult to achieve because of the lack of specific diagnosis tools. Species identification can benefit from a molecular approach. Trichoderma longibrachiatum is the most common species involved in these infections. Regardless of the type of infection, the prognosis was poor, with 8 deaths among 18 cases. This may be partially because of the resistance of these organisms to the majority of available antifungal agents, including amphotericin B. Trichoderma species now should be added to the growing list of emerging filamentous fungal pathogens.

Assessment of Culicoides barbosai as a vector of Mansonella ozzardi in Haiti.

Studies in the southern peninsula of Haiti showed that the biting midge, Culicoides barbosai, was capable of supporting the development of Mansonella ozzardi to the infective stage. The known vector, Culicoides furens, also was encountered. Both species showed distinct biting site preferences, i.e., 98% of the midges that engorged on the arms and head were C. barbosai whereas C. furens was collected mostly from the lower legs. Nine days after engorgement, 19 infective larvae were recovered from 13 C. barbosai versus six larvae from four C. furens. It was judged that C. barbosai may be as importantly involved in the natural transmission cycle as C. furens in this community.

Mansonella ozzardi in Haiti II. Arthropod vector studies.

The present vector studies show that the biting midge, Culicoides furens, serves as an intermediate host for Mansonella ozzardi in Haiti. A total of 3,430 C. furens were collected as they engorged on infected individuals. Under the maintenance conditions described herein, the microfilaria required 9 days to reach the infective stage. Approximately 43% of the midges survived, and from these 1,128 infective stage larvae were collected. This represents an overall infection rate of 0.76 larva per midge. Typically, there was a directly proportional relationship between the infection rate in midges and the level of microfilaremia in the individuals upon whom the C. furens fed. Also, the vector efficiency of C. furens collected from saltwater or freshwater breeding habitats was comparable.

Parasitological, serological, and clinical studies of Wuchereria bancrofti in Limbe, Haiti.

A survey for Wuchereria bancrofti in Limbe, Haiti (est. pop. = 10,500) revealed that 17% (231/1,450) had a patent infection. Nearly half of those surveyed harbored fewer than 10 microfilariae (mf) per 20 mm3 of finger-prick blood; the median mf density for females and males was 12.4 and 9.5, respectively. Parasitemias occurred as early as age 4. Antibody titers greater than or equal to 1:20 against adult D. viteae antigen were observed in 38% of microfilaremic individuals and in 29% of amicrofilaremic individuals. Peak antibody responsiveness (40%) was observed between 5 and 9 years of age. In all age groups there was no correlation between mf density and antibody titer. Among the mf carriers, 5.6% had no clinical symptoms. Lymphangitis was a common feature with 14.3% having lymphedema, 8.2% with edema of the lower extremities, and 1.3% reporting episodes of chyluria. Genital involvement among women was rare, but in males 5.4% had genital swelling and 4.5% had hydroceles. Culex pipiens quinquefasciatus (Say) was observed to support the complete development of W. bancrofti in Limbe.

Mansonella ozzardi in Haiti. I. Epidemiological survey.

A survey of 1,165 inhabitants of Bayeux, Haiti revealed that 16% were infected with Mansonella ozzardi. This was determined from a single 20 mm3 sample of finger prick blood from each individual. Amont children and young adults (< 20 years of age), fewer than 2% had detectable microfilaremias. Beyond this age the prevalence of infection for males and females was 49% and 24%, respectively. The microfilariae circulate in the peripheral blood with no significant periodicity. In general, the microfilaremias were low, with 71% of the positive cases having less than 10 microfilariae in 20 mm3 of blood; only 4% had more than 50 microfilariae. Histological examination of sectioned skin biopsies showed that the microfilariae dwell within the superficial capillary vessels; not free in the extravascular tissues.

Mansonella ozzardi in Haiti. III. A comparison of the sensitivity of four sampling methods in detecting infections.

A study to compare the sensitivity of four sampling methods in detecting Mansonella ozzardi among 133 inhabitants of Bayeux, Haiti, is reported. The Knott method proved the most sensitive with 40 microfilaria carriers detected. No additional infections were revealed by the other sampling methods. This was followed in order by 20 mm3 thick films of earlobe blood (34 cases), finger-prick blood (32 cases in the first sample), and skin biopsy (14 cases from paired samples). The combination of three finger-prick samples (60 mm3 of blood) detected 38 of 40 (95%) Knott-positive infections. The Knott method detected only one case not observed by at least one of the other three sampling methods. This sampling procedure did not detect more M. ozzardi in the 0-19-year age group than observed by the 20-mm3 finger prick method. Based on these results, a correction factor of 1.25 can be applied to our earlier Bayeux survey.

Mansonella ozzardi in Haiti. IV. Evaluation of antibody reactivity to heterologous antigens.

Sera from individuals in an area of Haiti endemic for Mansonella ozzardi were analyzed for reactivity to antigens of Brugia pahangi, Dirofilaria immitis, Mansonella llewellyni or Ascaris lumbricoides using either an enzyme-linked immunosorbent assay or an indirect immunofluorescent antibody test. IgM and IgG reactivity to all antigens was observed with sera from both microfilaremic and amicrofilaremic individuals when compared to reactivity of sera from individuals from nonendemic areas. Antibody reactivity to B. pahangi was greater than that to other antigens. IgG reactivity of sera from endemic patients to filarial antigens was consistently greater than that of IgM. Antibody reactivity was not correlated with age or microfilarial density.

Failure of falciparum malaria prophylaxis by mefloquine in travelers from West Africa.

Due to the spread of chloroquine-resistant strains of Plasmodium falciparum in French speaking parts of Africa, we have found it necessary to prescribe mefloquine for antimalaria prophylaxis to travelers to this area. Weekly doses of 125 or 250 mg have been recommended for short journeys. In spite of this regimen, 16 documented cases of falciparum malaria in travelers have been recorded in the Bordeaux hospital center since October, 1988. Fifteen of these patients were tourists returning from West African countries, and one was an Ivorian student who had been on vacation to his home country. Nine of these patients were evaluated and found to have high plasma mefloquine levels. This report strongly supports the existence of mefloquine-resistant falciparum malaria in West Africa, especially in Sierra Leone, Burkina Faso, and Cote d'Ivoire.

Assessment of Leptoconops bequaerti as a potential vector of Mansonella ozzardi in Haiti.

Experimental studies in Bayeux, Haiti showed that the biting midge, Leptoconops bequaerti, is capable of supporting the complete development of Mansonella ozzardi but only on a very limited scale. This suggests that the species may not be involved in the natural transmission cycle despite its abundance and pestiferous nature in certain areas of Haiti. A midge-holding container is described which markedly enhanced the survival of engorged L. bequaerti in the laboratory.