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Mansonellosis is caused by three filarial parasite species from the genus Mansonella that commonly produce chronic human microfilaraemias: M. ozzardi, M. perstans and M. streptocerca. The disease is widespread in Africa, the Caribbean and South and Central America, and although it is typically asymptomatic it has been associated with mild pathologies including leg-chills, joint-pains, headaches, fevers, and corneal lesions. No robust mansonellosis disease burden estimates have yet been made and the impact the disease has on blood bank stocks and the monitoring of other filarial diseases is not thought to be of sufficient public health importance to justify dedicated disease management interventions. Mansonellosis´s Ceratopogonidae and Simuliidae vectors are not targeted by other control programmes and because of their small size and out-door biting habits are unlikely to be affected by interventions targeting other disease vectors like mosquitoes. The ivermectin and mebendazole-based mass drug administration (iMDA and mMDA) treatment regimens deployed by the WHO´s Elimination of Neglected Tropical Diseases (ESPEN) programme and its forerunners have, however, likely impacted significantly on the mansonellosis disease burden, principally by reducing the transmission of M. streptocerca in Africa. The increasingly popular plan of using iMDA to control malaria could also affect M. ozzardi parasite prevalence and transmission in Latin America in the future. However, a potentially far greater mansonellosis disease burden impact is likely to come from shortcourse curative anti-Wolbachia therapeutics, which are presently being developed for onchocerciasis and lymphatic filariasis treatment. Even if the WHO´s ESPEN programme does not choose to deploy these drugs in MDA interventions, they have the potential to dramatically increase the financial and logistical feasibility of effective mansonellosis management.There is, thus, now a fresh and urgent need to better characterise the disease burden and ecoepidemiology of mansonellosis so that effective management programmes can be designed, advocated for and implemented. We would like to express our special thanks to María Belén García Fernández for helping us to draw the life-cycle of Mansonella species. JLC and SLBL also gratefully acknowledge support from the Fundação de Amparo à Pesquisa do Estado do Amazonas (FAPEAM; 062.01282/2018 and 002.00200/2019). And JLC would like to acknowledge support he receives from a Conselho Nacional de Desenvolvimento Científica e Tecnológico (CNPq) productivity grant. THTT is funded by a Sara Borrell contract from the Instituto de Salud Carlos III. Sí

Trypanosomes and filarial nematodes are important pathogens in humans and domestic animals. However, the majority of the infections reported from nonhuman primates (NHPs) are nonpathogenic. Moreover, those hemoparasites are relatively host-specific, which means that transmission from NHPs to humans is highly unlikely with the exception of nonpathogenic Trypanosoma rangeli and Trypanosoma cruzi and the T. brucei complex, which cause Chagas disease and sleeping sickness in humans, respectively. NHPs may also act as reservoir hosts for some nonpathogenic human filarial parasites, e.g., Mansonella streptocerca. Though many studies on those hemoparasites were conducted in the last century, recent studies remain rather neglected due to the logistical, ethical, and administrative challenges associated with the collection of blood or tissue samples in wild NHPs. In this chapter, we present an overview of trypanosomes and filarial nematodes infecting NHPs with information about their distribution, biology, pathogenesis, and their zoonotic potential.

Filariasis is a disease group affecting humans and animals caused by nematode parasites of the order Filariidae, commonly calledfilariae. Filarial parasites may be classified according to the habitat of the adult worms in the vertebral host. the lymphatic groupincludes Wucheria bancrofti, Brugia malayi and Brugia timori. the cutaneous group includes Loa-loa, onchocerca volvulus, andMansonella streptocerca. the body cavity group includes Mansonella perstans and Mansonella ozzardi. these parasites are transmittedto humans through the bite of an infected mosquito. Clinical findings vary from asymptomatic until severe, depending on geography,parasite species, immune response and intensity of the infection A 19-years-old Javanese woman, presented with oedema on right legs.She has been suffering from oedema on right leg since she was 7-years-old. Physical examination showed elephantiasis on the right leg.Early, the patient had swelling in right inguinal area spreading into her right leg. the oedema was persistent and become larger untilnow. there was no fever and pain. She had history living in South Borneo when she was 1 until 4 years old. She did not receive anymedication before. Laboratory examination showed no abnormality both of complete blood count and clinical chemistry. From thin bloodsmear examination many forms of microfilariae were found. the data showed manifestation of filariasis in the blood.

Human filariae are vector-borne parasites and the causative agents of various diseases, including human onchocerciasis and lymphatic filariasis. Onchocerciasis causes a spectrum of cutaneous and ophthalmologic manifestations (including blindness) and has long been a major public health problem in Bioko Island (Equatorial Guinea). Bioko Island has been included in the WHO's Onchocerciasis Control Program since 1987. In Bioko Island, the specificity and sensitivity of clinical Onchocerca volvulus diagnosis is key. The objective of this work was to update onchocerciasis elimination progress in Bioko Island, after 18 years of mass ivermectin intervention, and the general filariasis situation through a rapid and accurate molecular method. A cross-sectional study was conducted in Bioko Island from mid-January to mid-February 2014. A total of 543 subjects were included in the study. Whole blood and one skin snip (from lumbar regions) were analysed with a real time PCR assay. Two other skin biopsies were analysed by an expert microscopist. All positive samples were confirmed by sequencing. Traditional microscopic examination of the skin biopsies failed to detect any microfilariae. However, 11 (2.03%) infections were detected using PCR assay, including one O. volvulus, two Mansonella streptocerca, seven Mansonella perstans and one Loa loa infections. PCR assays in blood detected 52 filariae-positive individuals (9.6%) which harboured M. perstans or L. loa. The low prevalence of O. volvulus confirms the success of the Onchocerciasis Control Programme and suggests that Mass Drug Administration in Bioko Island can be interrupted in the near future. The very high prevalence of M. perstans found in skin snips assays raises doubts about the reliability of microscope-based diagnosis of O. volvulus infections.

Mansonellosis is a filarial disease caused by three species of filarial (nematode) parasites (Mansonella perstans, Mansonella streptocerca, and Mansonella ozzardi) that use humans as their main definitive hosts. These parasites are transmitted from person to person by bloodsucking females from two families of flies (Diptera). Biting midges (Ceratopogonidae) transmit all three species of Mansonella, but blackflies (Simuliidae) are also known to play a role in the transmission of M. ozzardi in parts of Latin America. M. perstans and M. streptocerca are endemic in western, eastern, and central Africa, and M. perstans is also present in the neotropical region from equatorial Brazil to the Caribbean coast. M. ozzardi has a patchy distribution in Latin America and the Caribbean. Mansonellosis infections are thought to have little pathogenicity and to be almost always asymptomatic, but occasionally causing itching, joint pains, enlarged lymph glands, and vague abdominal symptoms. In Brazil, M. ozzardi infections are also associated with corneal lesions. Diagnosis is usually performed by detecting microfilariae in peripheral blood or skin without any periodicity. There is no standard treatment at present for mansonellosis. The combination therapy of diethylcarbamazine plus mebendazole for M. perstans microfilaremia is presently one of the most widely used, but the use of ivermectin has also been proven to be very effective against microfilariae. Recently, doxycycline has shown excellent efficacy and safety when used as an antimicrobial against endosymbiotic Wolbachia bacteria harbored by some strains of M. perstans and M. ozzardi. Diethylcarbamazine and ivermectin have been used effectively to treat M. streptocerca infection. There are at present no estimates of the disease burden caused by mansonellosis, and thus its importance to many global health professionals and policy makers is presently limited to how it can interfere with diagnostic tools used in modern filarial disease control and elimination programs aimed at other species of filariae. Sí

Background The association between parasites and urticaria was first suggested in the last century. A wide range, 0-75.4%, of the prevalence of parasitic infection has been reported with chronic urticaria (CU). Moreover, urticaria may be detected in patients with parasitosis. Nematodes are a type of helminth that infect hundreds of millions of people throughout the world. Objective The aim of this work was to collect and review the published studies and cases of urticaria associated with nematode infections. Methods A search of scientific literature data bases from January 1960 until May 2017 was carried out. Results Numerous nematode infections have been associated with urticaria and/or angioedema: Anisakis simplex, Ascaris species (spp.), Dirofilaria spp., Enterobius vermicularis, Gnathostoma spp., Loa loa, Mansonella streptocerca; Necator americanus, Onchocerca volvulus, Strongyloides stercoralis, Toxocara spp., Trichinella spp., and Wuchereria bancrofti. The pathogenesis of urticaria in these infections generally remains unexplained. In some cases, skin manifestations were caused by the presence of the worm in the skin (Filaria, Gnathostoma); in other cases, such as A. simplex and S. stercoralis infections, there was a clear immunoglobulin E-mediated mechanism that led to allergic reactions, and infection and allergy coexisted; for other nematodes, the association was anecdotal and only a few cases were reported. Conclusion It is difficult to detect a certain causal effect, except when urticaria improves or disappears after infection treatment. Cases of isolated urticaria not associated with other symptoms rarely may be caused by helminths. In the current guideline for urticaria, parasitosis is considered to be a rare possible cause of CU in developed industrial countries, Therefore, although a routine screening of parasitic infection in CU is not recommended, in our opinion, testing a patient with urticaria for parasites is a physician's choice based on the characteristics of the patient, such as associated symptoms, dietary habit, provenance country and previous travel.

Human mansonellosis is caused by M. perstans, M. ozzardi and M. streptocerca, the three main filarial species in the genus Mansonella. Despite accumulating evidence of a high prevalence in endemic areas, there is currently no filariasis control programme targeting mansonellosis. The health-related impact on people living with these filariae remains unknown, and evidences regarding treatment strategies are scarce. Like other neglected diseases, it mainly affects poor populations living in tropical and subtropical climates. Mansonellosis can be considered one of the most neglected tropical infectious diseases. The objective of this literature review was to draw attention to the gap of knowledge regarding Mansonella spp. taxonomy, the transmission of these arthropod-borne filariasis and the health outcomes of people living with mansonellosis. Keywords: Filariasis, Mansonella perstans, Mansonella ozzardii, Mansonella streptocerca, neglected tropical diseases

Summary Bioko is the only island known in the world with endemic onchocerciasis. The island's rural communities consist of villages and cocoa plantations inhabited by Bubi and Fang ethnic groups. The aim of this study was to evaluate the impact of 8 years of vertical ivermectin distribution on the prevalence and intensity of Onchocerca volvulus infection in the rural population by means of pre- (1989) and post-long term treatment (1998) epidemiological surveys. In both surveys, the entire population of 12 randomly selected communities (1723 and 1082 individuals) was examined. The mean ivermectin therapeutic coverage for the 8 years was 53.2%. Iliac crest skin snips were used for differential diagnosis between O. volvulus and Mansonella streptocerca. The crude O. volvulus infection prevalence before ivermectin intervention was 74.5% (1284/1723); after the intervention it was 38.4% (415/1082). The Community Microfilarial Load (CMFL) before and after ivermectin intervention was 28.29 microfilariae/snip vs. 2.32 microfilariae/snip. The reduction in prevalence and CMFL after eight annual rounds of ivermectin treatment corroborates the drug microfilaricidal activity and good tolerability. In the pre-treatment survey, the prevalence was higher in the Bubi group (77.1%, 1126/1461); post-treatment it was higher among the Fang (51.1%, 92/180). The reduction in prevalence and intensity of O. volvulus infection differed between ethnic groups and communities. Bioko est la seule ile dans le monde connue comme etant endemique pour l'onchocercose. Les communautes rurales de l’ile consistent en villages et plantations de cacao habites par les groupes ethniques Bubi et Fang. Le but de cette etude etait d’evaluer l'impact de 8 annees de distribution verticale d'ivermectine sur la prevalence et l'intensite de l'infection aOnchocerca volvulus dans la population rurale, au moyen d'enquetes epidemiologiques avant (1989) et apres (1998) une longue periode de traitement. Dans toutes les deux enquetes, la population entiere de 12 communautes selectionnees aleatoirement (1723 versus 1082 individus) a ete examinee. La couverture moyenne du traitement a l'ivermectine durant les 8 annees etait de 53,2%. Les biopsies cutanees exsangues au-dessus des cretes iliaques ont ete utilisees pour le diagnostic differentiel entre O. volvulus et Mansonella streptocerca. La prevalence brute de l'infection aO. volvulusetait de 74,5% (1284/1723) avant et de 38,4% (415/1082) apres l'intervention a l'ivermectine. La charge de microfilaire communautaire avant l'intervention etait de 28,29 microfilaire/crete contre 2,32 apres. La reduction de la prevalence et de la charge de microfilaire communautaire apres 8 annees de traitement a l'ivermectine corrobore avec l'activite microfilaricide et la bonne tolerance du medicament. Dans l'enquete avant le traitement, la prevalence etait plus elevee dans le groupe Bubi (77,1%; 1126/1461), apres traitement, elle etait plus elevee dans le groupe Fang (51,1%; 92/180). La reduction de la prevalence et de l'intensite de l'infection aO. volvulus varie selon le groupe ethnique et la communaute. Bioko es la unica isla del mundo endemica para oncocercosis. Las comunidades rurales de la isla consisten en poblados y plantaciones de cocoa, habitadas por los grupos etnicos Bubi y Fang. El objetivo de este estudio era evaluar el impacto de 8 anos de distribucion vertical de ivermectina entre la poblacion rural, sobre la prevalencia e intensidad de infeccion por Onchocerca volvulus. Con este fin se realizaron encuestas epidemiologicas antes (1989) y despues de tratamiento a largo plazo (1998). En ambas encuestas se examino a toda la poblacion de doce comunidades elegidas al azar (1723 y 1082 individuos). La media de la cobertura terapeutica para los 8 anos fue del 53.2%. Se utilizaron biopsias cutaneas de la cresta iliaca para el diagnostico diferencial entre O. volvulus y Mansonella streptocerca. La prevalencia cruda de infeccion por O. volvulus antes de la intervencion con ivermectina era del 74.5% (1284/1723); despues de la intervencion era del 38.4% (415/1082). La carga de microfilarias comunitaria (CMC), antes y despues de la intervencion con ivermectina, fue de 28.29 microfilarias/biopsia versus 2.32 microfilarias/biopsia. La reduccion en la prevalencia y la CMC despues de 8 rondas anuales de tratamiento con ivermectina, corroboran tanto la actividad microfilaricida del medicamento como su buena tolerancia. En la encuesta realizada antes del tratamiento, la prevalencia era mayor en el grupo Bubi (77.1%,1126/1461), mientras que el la realizada post-tratamiento fue mayor entre los Fang (51.1%,92/180). La reduccion en la prevalencia e intensidad de infeccion por O. volvulus difirio entre grupos etnicos y comunidades.

Threadlike filarial nematodes have been identified as the causative agent of filariasis. Cutaneous filariasis is caused primarily by Loa loa, Onchocerca volvulus, and Mansonella streptocerca. These parasites occupy the subcutaneous layer of the skin. However, other filarial parasites are usually associated with varying degrees of dermatological manifestations. In the present discourse, two cases of cutaneous filariasis were diagnosed in two female patients (21 and 40 years old, respectively) in Remitch Clinic and Maternity located in a nonriverine community in Ekpoma, Edo State, Nigeria. In this report, patients with body mass index (BMI) of 18.97 and 23.45 kg/m2, respectively, presented on two different occasions at least 6 months apart with hyperpigmented skin lesions in the upper and lower limbs, respectively. There was associated intense pruritus with no evidence of lymphadenopathy and lymphoedema. Following laboratory confirmation of filariasis, the patients were placed on a single oral dose combination of albendazole (400 mg) + ivermectin (200 mcg/kg), while oral doses of loratadine 10 mg were administered daily for 5 days. Patients were carefully followed up for 6 weeks during which recession of the lesion and untoward reactions were monitored. It was observed that within 6 weeks of treatment, there was a dramatic recession of skin lesion. Adverse effect reported from use of the combination was mild. This case report revealed that cutaneous filariasis is not an uncommon presentation of filariasis infestation in Nigeria. The report also validates the safety and efficacy of the combination in the management of cutaneous manifestation of the disease.

Mansonelliasis is a filariasis whose etiological agents are Mansonella ozzardi, Mansonella perstans and Mansonella streptocerca. Only the first two cited species occur in Brazil. M. ozzardi is widely distributed in Amazonas state and it is found along the rivers Solimoes, Purus, Negro and their tributaries while M. perstans is restricted to the Upper Rio Negro. In this update, we report the occurrence of M. ozzardi in Amazonas since the 1950s, and we show that over the years this filariasis has been sustained with high prevalence, while maintaining a constant cycle of transmission in endemic areas due to the lack of treatment and control policies. M. perstans has so far only been recorded in indigenous populations in the Upper Rio Negro. However, the continuous flow of migrants to other regions may cause an expansion of this infection.

The protein Ov20/OvS1 was used as antigen in enzyme-linked immunosorbent assay (ELISA) and Western blot in order to differentiate onchocerciasis from African mansonelliasis and to characterize the hyperreactive form of Onchocerca volvulus infection (sowda). The specificity of the immunoglobulin G4 (IgG4) Western blot was 98% for the differentiation between persons with onchocerciasis and Mansonella microfilariae (mf) carriers (125 persons with Mansonella perstans and 92 with Mansonella streptocerca) whereas the IgG4 ELISA showed a specificity of 81% in 137 M. perstans mf carriers and 85% in 94 M. streptocerca mf carriers. The sensitivity of Ov20/OvS1 in identifying onchocerciasis using the IgG4 ELISA was 75% for 103 O. volvulus mf carriers with the generalized and 89% for 44 patients with the sowda form of onchocerciasis. Immunoglobulin E antibodies against OvS1 were found in 95% of 39 patients with hyperreactive onchocerciasis but only in 15% of 47 persons with the generalized form. Thus Ov20/OvS1 appears to be a promising candidate antigen for the diagnosis of onchocerciasis and in particular for the detection of the sowda type of disease. (authors)

The prevalence of filarial infections in the tropics is second only to that of geohelminth (soil-transmitted helminth) infections. Filarial infections in humans include the various forms of lymphatic filariasis (Wuchereria bancrofti, Brugia malayi, and B. timori), onchocerciasis (Onchocerca volvulus), loiasis (Loa loa), and mansonellosis (Mansonella streptocerca, M. perstans, and M. ozzardi). About 120 million people currently have lymphatic filariasis, and about 1 billion people are considered to be at risk for infection. Lymphatic filariasis remains endemic in 81 countries and is prevalent on all continents except Australia. Approximately 37 million people have . . .

During filaria surveys Mansonella streptocerca was found for the first time in Uganda, in 12 widely scattered villages in the Bundibugyo district between the Ruwenzori mountains and the Ituri forest, an area not endemic for Onchocerca volvulus. The crude prevalence in 806 examined adult persons ranged from 5 to 89% with an average of 61%. In 148 children the prevalence was 36%. The geometric mean of microfilaria (mf) densities in adult mf carriers was 1.7 mf/mg skin and the community microfilarial loads ranged from 1.0 to 13.7 mf/skin snip. In 476 persons skin snips from the shoulder contained mf in 58% and those from the buttocks in 48%. Skin snips from 68 persons digested with collagenase showed that only 30-37% of the mf emerged during 24 h incubation at 30 degrees C in isotonic salt solution. An itching acute or more often chronic papular dermatitis, predominantly on the upper parts of the body, was the typical skin lesion observed in 24% of 177 M. streptocerca mf carriers.

Filariasis is caused by thread-like nematode worms, classified according to their presence in the vertebrate host. The cutaneous group includes Onchocerca volvulus, Loa loa and Mansonella streptocerca; the lymphatic group includes Wuchereria bancrofti, Brugia malayi and Brugia timori and the body cavity group includes Mansonella perstans and Mansonella ozzardi. Lymphatic filariasis, a mosquito-borne disease, is one of the most prevalent diseases in tropical and subtropical countries and is accompanied by a number of pathological conditions. In recent years, there has been rapid progress in filariasis research, which has provided new insights into the pathogenesis of filarial disease, diagnosis, chemotherapy, the host–parasite relationship and the genomics of the parasite. Together, these insights are assisting the identification of novel drug targets and the discovery of antifilarial agents and candidate vaccine molecules. This review discusses the antifilarial activity of various chemical entities, the merits and demerits of antifilarial drugs currently in use, their mechanisms of action, in addition to antifilarial drug targets and their validation.

We developed a polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA) for the detection of Onchocerca volvulus DNA. To standardize the PCR and to avoid false-negative results, an internal control DNA was co-amplified by the same set of primers. We differentiated the wild-type PCR product of the O-150 DNA sequence from the internal control by specific DNA probes. Detection of biotinylated PCR products by DNA probes was performed by ELISA to quantify the PCR product or by DNA Detection Test Strips as a rapid field technique. The methods were evaluated on skin biopsies from individuals living in an area endemic for O. volvulus in Uganda, but with low microfilaria densities because of ivermectin treatment. Microfilaria density was assessed by a single skin snip and a second skin snip was examined by PCR. Among 69 samples from microfilaria carriers, 47 (68%) were positive by ELISA and 55 (80%) by test strip detection of PCR products. When 39 samples of microfilaria-negative individuals from the same area were tested, 10 (27%) were positive by ELISA and 12 (31%) by test strips. None of the 19 samples obtained from persons living in an area not endemic for O. volvulus but endemic for Mansonella streptocerca was positive in either test. Although the ELISA is theoretically more sensitive than the test strips for the detection of PCR products, examination of field samples revealed that the test strip method had a higher operational sensitivity and was more convenient to perform. Thus, the DNA Detection Test Strips are a rapid and low-tech tool for identification of PCR products in laboratories of countries endemic for onchocerciasis.

The long-term effect of a single oral dose of 150 microg/kg of body weight of ivermectin on Mansonella streptocerca microfilariae was studied in western Uganda. Before treatment, the geometric mean microfilaria density (mf) in 93 infected persons was 2.4 mf/mg of skin (range, 0.1-42.6). One year after treatment, 43 persons (46%) were microfilaria-negative, and the geometric mean in the remaining persons dropped significantly, to 0.7 mf/mg (range, 0.1-6.9). Thus, ivermectin is highly effective against M. streptocerca, and a single dose leads to a sustained suppression of microfilariae in skin. In Africa, ivermectin is used for mass treatment to control Onchocerca volvulus and Wuchereria bancrofti. Because these filarial parasites are often coendemic with M. streptocerca, the treated population may receive the additional benefit of suppression of M. streptocerca microfilariae.

To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic for M. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could be detected in 16 samples thought to be microfilaria negative. Furthermore, six days following ivermectin treatment, M. streptocerca DNA was found in 12 of 14 microfilaria-negative biopsies. Control skin samples from patients infected with O. volvulus were all negative in the nested PCR assay. This assay improves the diagnosis of M. streptocerca and will facilitate further epidemiologic studies.

Immunologic analyses of sera from 47 selected individuals living in a mixed filariasis transmission zone in Gabon were carried out. Onchocerca volvulus, Loa loa, Mansonella streptocerca, and M. perstans are transmitted in this region. Based on parasitologic findings and age, the 47 individuals were stratified into four groups: microfilaria negative (Mf-) children (3–15 years old), Mf- adults (> 15 years old), microfilaria positive (Mf+) children and Mf+ adults. For descriptive purposes, the term microfilaria positive refers to individuals with skin and blood microfilariae. Antifilarial antibody titers were determined using an enzyme-linked immunosorbent assay with Dipetalonema viteae antigens. In general, children had higher titers of IgG antibodies than adults. For the IgG1, IgG2, and IgG3 subclass responses, both age and microfilarial status appeared to be important variables since Mf- children consistently had the highest titers whereas Mf- adults had the lowest titers. For the IgG4 antifilarial response, only the microfilarial status was an important variable. All Mf+ individuals had significantly higher levels of IgG4 antibody than Mf- individuals. Pooled sera of Mf- and Mf+ individuals reacted with similar O. volvulus antigens on Western blots. Control sera of individuals who did not reside in the study area, but who had single infections with L. loa or M. perstans, did not react with any O. volvulus antigens.

1934 Bantus and 379 Pygmies were investigated for Loa loa and Mansonella perstans filariasis in 7 villages in the Chaillu forest of the Congo. Bantus were more frequently infected with L. loa than Pygmies (18·9% of microfilariae carriers compared with 10·6%). In individuals over 30 years of age, males were more frequently infected than females. Microfilarial densities increased until the age of 20 years and then remained stable. Parasite load was not significantly different in the two ethnic groups. For mansonelliasis, the microfilarial rate was higher in the Pygmies (67·5% compared with 22·0%) and males of the 2 groups were more frequently infected than females. Microfilarial load was also higher in Pygmies than in Bantus (mean microfilarial densities (MfD 50) 13 and 2 respectively). In the Pygmy group, MfD 50 for M. perstans increased with age whereas it remained stable in the Bantus. 53·8% of the 249 questioned persons had experienced worm migration under the conjunctiva. Both ethnic groups were equally exposed to the vectors of L. loa and reasons for the difference in prevalence of microfilaria carriers are discussed. For mansonelliasis increased contact with vectors may explain the higher degree of infestation observed in Pygmies. Other filariases were infrequent in ( Mansonella streptocerca ), or absent from ( Onchocerca volvulus and Wuchereria bancrofti ), the study area.

In 75 biopsy specimens of skin from 34 patients with streptocerciasis who had been treated with diethylcarbamazine, we found 39 female and six male adult Dipetalonema streptocerca in the dermal collagen. This is the first report of adult male D. streptocerca in man, and identifying features are described.

1. (1) In the dosage used, hetrazan is as effective as oil of chenopodium in the treatment of ascariasis. 2. (2) The production of skin irritation in about a quarter of the cases treated, and the reed for daily dosage for 4 days, make hetrazan unsuitable for the treatment of ascariasis in the Gold Coast. 3. (3) The relation of skin irritation after hetrazan to streptocerciasis is discussed.