Molecular Epidemiology of Mansonella Species in Gabon.

Mansonella perstans, a filarial nematode, infects large populations in Africa and Latin America. Recently, a potential new species, Mansonella sp "DEUX," was reported. Carriage of endosymbiotic Wolbachia opens treatment options for Mansonella infections. Within a cross-sectional study, we assessed the prevalence of filarial infections in 834 Gabonese individuals and the presence of the endosymbiont Wolbachia. Almost half of the participants (400/834 [48%]) were infected with filarial nematodes, with Mansonella sp "DEUX" being the most frequent (295/400 [74%]), followed by Loa loa (273/400 [68%]) and Mansonella perstans (82/400 [21%]). Being adult/elderly, male, and living in rural areas was associated with a higher risk of infection. Wolbachia carriage was confirmed in M. perstans and Mansonella sp "DEUX." In silico analysis revealed that Mansonella sp "DEUX" is not detected with currently published M. perstans-specific assays. Mansonella infections are highly prevalent in Gabon and might have been underreported, likely also beyond Gabon.

Mansonella ozzardi mitogenome and pseudogene characterisation provides new perspectives on filarial parasite systematics and CO-1 barcoding.

Despite the broad distribution of M. ozzardi in Latin America and the Caribbean, there is still very little DNA sequence data available to study this neglected parasite's epidemiology. Mitochondrial DNA (mtDNA) sequences, especially the cytochrome oxidase (CO1) gene's barcoding region, have been targeted successfully for filarial diagnostics and for epidemiological, ecological and evolutionary studies. MtDNA-based studies can, however, be compromised by unrecognised mitochondrial pseudogenes, such as Numts. Here, we have used shot-gun Illumina-HiSeq sequencing to recover the first complete Mansonella genus mitogenome and to identify several mitochondrial-origin pseudogenes. Mitogenome phylogenetic analysis placed M. ozzardi in the Onchocercidae "ONC5" clade and suggested that Mansonella parasites are more closely related to Wuchereria and Brugia genera parasites than they are to Loa genus parasites. DNA sequence alignments, BLAST searches and conceptual translations have been used to compliment phylogenetic analysis showing that M. ozzardi from the Amazon and Caribbean regions are near-identical and that previously reported Peruvian M. ozzardi CO1 reference sequences are probably of pseudogene origin. In addition to adding a much-needed resource to the Mansonella genus's molecular tool-kit and providing evidence that some M. ozzardi CO1 sequence deposits are pseudogenes, our results suggest that all Neotropical M. ozzardi parasites are closely related.

Occurrence of Mansonella ozzardi diagnosed using a polycarbonate membrane in a riverside population of Lábrea in the Western Brazilian Amazon.

INTRODUCTION Mansonella ozzardi is a widely distributed filaria worm in the Amazon region. This study aimed to determine the prevalence of M. ozzardi infection in riverine communities of Lábrea municipality, Amazonas State, Brazil. METHODS A diagnostic blood filtration method in a polycarbonate membrane was used. RESULTS M. ozzardi was found in 50.3% of the sample, with the highest prevalence in farmers/fishermen (69.4%; χ 2 = -19.14, p<0.001). The prevalence was higher in longer-term residents (≥11 years; 60.2%). CONCLUSIONS M. ozzardi infection rates are high near the Purus River, much greater than those previously reported based on diagnosis using thick blood smears.

Review of the genus Mansonella Faust, 1929 sensu lato (Nematoda: Onchocercidae), with descriptions of a new subgenus and a new subspecies.

Based on material deposited in museum collections, twelve species within Mansonella sensu lato were examined and their descriptions amended. Based on additional morphological details, the erection of the new monotypic subgenus Filyamagutia Bain & Uni for M. (F.) akitensis (Uni, 1983), and the new combination M. (Pseudolitomosa) musasabi (Yamaguti, 1941) Bain & Uni are proposed. A new subspecies, M. (Tetrapetalonema) atelensis amazonae Bain & Guerrero is described and a key to the seven subgenera of Mansonella is provided. Furthermore, the elevation of Sandnema to full genus rank comprising the two species S. digitatum (Chandler, 1929) n. comb. and S. sunci (Sandground, 1933) n. comb., is proposed. Host and geographic records for the species of Mansonella and Sandnema are included.

Mansonella ozzardi (Nematoda: Onchocercidae) in the riverine population of the Tefé River, State of Amazonia, Brazil.

INTRODUCTION: This study assessed the prevalence of Mansonella ozzardi in riverine communities of the Tefé River, Amazonas, Brazil. METHODS: The prevalence of M. ozzardi was estimated by microscopic examination of thick blood smears. RESULTS: The M. ozzardi prevalence rate was 6.3% (19/300). Filarial infection was found in 8 of the 11 communities surveyed, with prevalence rates varying from 2.5% to 22.2%. CONCLUSIONS: Tefé is a region of oil and natural gas exploration, in which there is a high turnover of workers. Migration patterns may facilitate the dissemination of mansonelliasis to other regions.

Mansonella ozzardi (Nematoda: Onchocercidae) in the riverine population of the Tefé River, State of Amazonia, Brazil

Introduction: This study assessed the prevalence of Mansonella ozzardi in riverine communities of the Tefé River, Amazonas, Brazil. Methods: The prevalence of M. ozzardi was estimated by microscopic examination of thick blood smears. Results: The M. ozzardi prevalence rate was 6.3% (19/300). Filarial infection was found in 8 of the 11 communities surveyed, with prevalence rates varying from 2.5% to 22.2%. Conclusions: Tefé is a region of oil and natural gas exploration, in which there is a high turnover of workers. Migration patterns may facilitate the dissemination of mansonelliasis to other regions. .

Genetic characterization of atypical Mansonella (Mansonella) ozzardi microfilariae in human blood samples from northeastern Peru.

DNA sequence comparisons are useful for characterizing proposed new parasite species or strains. Microfilariae with an atypical arrangement of nuclei behind the cephalic space have been recently described in human blood samples from the Amazon region of Peru. Three blood specimens containing atypical microfilariae were genetically characterized using three DNA markers (5S ribosomal DNA, 12S ribosomal DNA, and cytochrome oxidase I). All atypical microfilariae were clustered into the Mansonella group and indistinguishable from M. ozzardi based on these DNA markers.

Mansonella perstans filariasis in Africa.

Mansonella perstans is a vector-borne human filarial nematode, transmitted by tiny blood-sucking flies (biting midges). It is widespread in many parts of Sub-Saharan Africa and also occurs in parts of Central and South America. Despite the commonness of this parasite very few studies have been carried out on its epidemiology and on the morbidity resulting from it, and only few thorough drug trials have been conducted to look for effective and suitable drugs and drug regimens for treatment and control. Here, we review currently available knowledge on M. perstans infections in Africa, including documented aspects of biology, vectors, transmission, diagnosis, epidemiology, morbidity and treatment. It is concluded that there is an urgent need for more research on this widespread but greatly neglected infection in order to properly assess its public health significance and as a background for identifying and recommending optimal means and strategies for treatment and control.

Nested PCR to detect and distinguish the sympatric filarial species Onchocerca volvulus, Mansonella ozzardi and Mansonella perstans in the Amazon Region.

We present filaria-nested polymerase chain reaction (PCR), which is based on amplification of first internal transcribed spacer rDNA to distinguish three parasitic filarial species (Onchocerca volvulus, Mansonella ozzardi and Mansonella perstans) that can be found in the Amazon Region. Nested PCR-based identifications yielded the same results as those utilizing morphological characters. Nested PCR is highly sensitive and specific and it detects low-level infections in both humans and vectors. No cross-amplifications were observed with various other blood parasites and no false-positive results were obtained with the nested PCR. The method works efficiently with whole-blood, blood-spot and skin biopsy samples. Our method may thus be suitable for assessing the efficacy of filaria control programmes in Amazonia by recording parasite infections in both the human host and the vector. By specifically differentiating the major sympatric species of filaria, this technique could also enhance epidemiological research in the region.

An atypical microfilaria in blood samples from inhabitants of Brazilian Amazon.

An unidentified microfilaria sharing characteristics with Mansonella ozzardi and Onchocerca volvulus was detected in blood samples from seven human volunteers, inhabitants of a community in the border of Amazonas and Acre State. They were detected during epidemiological studies carried out in some communities along Antimary, Acre, and Purus Rivers in the Brazilian Amazon. The most striking difference was presented in the shape of the cephalic space from this microfilaria which was different from those of M. ozzardi and with similarities to O. volvulus in this region, but no remarkable differences were observed at the caudal region. More accurate studies are being carried out in order to provide additional data and supporting evidences before establishment of a new species can be done.

Prevalence and molecular phylogenetic characterization of Trypanosoma (Megatrypanum) minasense in the peripheral blood of small neotropical primates after a quarantine period.

Neotropical primates of the Cebidae and Callitrichidae, in their natural habitats, are frequently infected with a variety of trypanosomes including Trypanosoma cruzi, which causes a serious zoonosis, Chagas' disease. The state of trypanosome infection after a 30-day quarantine period was assessed in 85 squirrel monkeys (Saimiri sciureus) and 15 red-handed tamarins (Saguinus midas), that were wild-caught and exported to Japan as companion animals or laboratory animals, for biomedical research, respectively. In addition to many microfilariae of Mansonella (Tetrapetalonema) mariae at a prevalence of 25.9%, and Dipetalonema caudispina at a prevalence of 3.5%, a few trypomastigotes of Trypanosoma (Megatrypanum) minasense were detected in Giemsa-stained thin films of blood from 20 squirrel monkeys at a prevalence of 23.5%. Although few T. minasense trypomastigotes were found in Giemsa-stained blood films from tamarins, a buffy-coat examination detected trypanosomes in 12 red-handed tamarins (80.0%), and PCR amplification of a highly variable region of the small subunit ribosomal RNA genes (SSU rDNA) for Trypanosoma spp. detected the infection in 14 of the 15 tamarins (93.3%). Nucleotide sequences of the amplicons were identical for trypanosomes from tamarins and squirrel monkeys, indicating a high prevalence but low parasitemia of T. minasense in imported Neotropical nonhuman primates. Based on the SSU rDNA and 5.8S rDNA, the molecular phylogenetic characterization of T. minasense indicated that T. minasense is closely related to trypanosomes with Trypanosoma theileri-like morphology and is distinct from Trypanosoma (Tejeraia) rangeli, as well as from T. cruzi. Using some blood samples from these monkeys, amplification and subsequent sequencing of the glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) gene fragments detected 4 trypanosome genotypes, including 2 types of T. cruzi clade, 1 type of T. rangeli clade, and 1 T. rangeli-related type, but failed to indicate its phylogenetic position based on the gGAPDH gene. Furthermore, species ordinarily classified in the Megatrypanum by morphological criteria do not form a clade in any molecular phylogenetic trees based on rDNA or gGAPDH genes.

Affinities between Cutifilaria (Nematoda: Filarioidea), parasites of deer, and Mansonella as seen in a new onchocercid, M. (C.) perforata n. sp., from Japan.

A new dermal filarioid nematode, collected from Cervus nippon nippon (sika deer) on Kyushu Island, Japan, showed close affinities between the genera Cutifilaria and Mansonella (Onchocercidae: Onchocercinae): no buccal capsule, esophagus reduced to a thin fibrous tube, and female tail with four lappets. We propose Cutifilaria as a subgenus of Mansonella. Cutifilaria was distinguished from the five other subgenera, Mansonella, Tetrapetalonema, Esslingeria, Sandnema, and Tupainema, in having an area rugosa composed of transverse bands with tiny points, 14-16 papillae around the cloacal aperture, two prominent rhomboidal subterminal papillae, and a thick right spicule with spoon-shaped distal extremity. The host range of Mansonella was extended to ungulates by the addition of Cutifilaria, which appears to be derived from Tupainema, parasitic in Tupaioidea (insectivores), because of the similarity in their right spicules; Cutifilaria seems to have an Asiatic origin. M. (C.) perforata n. sp. was distinct from the sole other related species, M. (C.) wenki, a parasite of Cervus elaphus (red deer) in Europe, having a more complex right spicule with a sturdy terminal point and microfilariae with a bifid posterior end. In addition, almost all females had cuticular pores near the vulva, on the ventral line. The prevalence of microfiloriae and adults of M. (C.) perforata in the skin of sika deer was 38% and 21%, respectively.

Characterisation of nuclear ribosomal DNA sequences from Onchocerca volvulus and Mansonella ozzardi (Nematoda: Filarioidea) and development of a PCR-based method for their detection in skin biopsies.

The internal transcribed spacer region (ITS1, 5.8S gene and ITS2) of the two filarial nematodes Onchocerca volvulus and Mansonella ozzardi was sequenced, and two species-specific primers designed in the ITS2 to develop a PCR-based method for their specific detection and differentiation. When used with a universal reverse primer, the two species-specific primers gave amplification products of different size, which were readily separated in an agarose gel. The PCR was tested on skin biopsies from 51 people from three localities in Brazil where M. ozzardi is present, and results have been compared with those of parasitological examination of blood. The species-specific PCR gave a higher percentage of detection of infection by M. ozzardi than the parasitological examination of blood. No infection with O. volvulus was detected by PCR. This PCR-based assay may assist in determining the nature of infection in areas where both filarial species exist in sympatry.

Environmental factors and the distribution of mansonelliases in southern Venezuela.

The distribution of mansonelliases and their relation to various quantitative criteria were determined through the study of 1,057 subjects in 17 localities in ten regions of Amazonas State and Bolívar State. The total prevalence among the blood samples, determined through the Knott technique, was 18.54%. 11.26% were parasited by Mansonella perstans, 9.93% by Mansonella ozzardi, and 2.63% by both species. The average of microfilaremia was 48.19 mf/mL of blood in M. perstans and 13.79 mf/mL in M. ozzardi. In the regions studied, M. ozzardi has a wider area of distribution than M. perstans. Prevalence, average number of parasites per host, and the infection index have a positive and statistically significant correlation with the total annual precipitation mean for each region for M. perstans; in the case of M. ozzardi the quantitative parameters are positively correlated with the altitude of each region, this correlation being statistically significant. With respect to type of vegetation, M. perstans had a higher infection index in Amazonian caatinga transition in pluvial lowland forest, and M. ozzardi in semideciduous forest of the alisio type. Therefore two types of transmission, M. ozzardi-Simulium and M. perstans-Culicoides are suggested.

Filariae from a wild gorilla in Gabon with description of a new species of Mansonella.

A search for filariae was performed on a wild male Gorilla g. gorilla from the Lopé Reserve in Gabon, which had died as a result of injuries inflicted by another male gorilla. A female worm of Loa loa and female worms of two species of Mansonella were recovered from the deep tissues of a wounded thigh. In order to analyze these Mansonella, specimens of M. (E.) perstans, M. (E.) vanhoofi and M. (E.) streptocerca from the Collections of the Museum National d'Histoire Naturelle de Paris have been studied and new important discriminative characters characterised, such as the body-swellings in M. (E.) perstans, due to the presence of coelomocytes as in South-american M. (Tetrapetalonema) spp. One of the Mansonella from this gorilla was not identified, but the body-swellings and the microfilarial morphology suggested a possible similarity with M. (Esslingeria) perstans. The other species is new; M. (E.) lopeensis n. sp. is distinguished by its large size, lack of body-swellings, structure of the tegumental sheath, complex vagina, and a tail with a subterminal constriction, a terminal bend and large lappets. Histological sections of organs of this gorilla also showed a microfilaria of M. (E) leopoldi in the blood vessels of the liver, and a male of Mansonella sp., interestingly situated in an afferent lymphatic vessel of an axillary lymph node.(ABSTRACT TRUNCATED AT 250 WORDS)

The genus Mansonella (syn. Tetrapetalonema): a new classification.

Mansonella has been established as a valid genus, and Tetrapetalonema synonymized with it. Comparative morphological studies have resulted in the restructuring of the Mansonella group. The genus is characterized by the following features: cuticular pre-esophageal ring absent; esophagus slender, poorly differentiated; female tail with four terminal papillae; caudal papillae in male typically clustered around cloaca; and, microfilariae without sheath. Twenty-four species are assigned to the genus Mansonella. Five subgenera are proposed to accommodate these species. The subgeneric groups are distinguished principally on morphological criteria, although host range and geographical distribution are considered. The following systematic classification is proposed: Mansonella (Mansonella) subgen. n., to accommodate those species which have the following morphological features: cephalic extremity with dorsoventral orientation; male tail with tip flattened dorsoventrally; vulva in midesophageal region; and microfilariae without nuclei extending to tip of tail. Type species is M. (M.) ozzardi. Mansonella (Tupainema) subgen. n., to accommodate the single species M. dunni with the following characters: cephalic extremity with lateral orientation and body constricted to form cephalic extremity in shape of hemisphere narrower than body behind it; tip of male tail not flattened dorsoventrally; vulva at or posterior to base of esophagus; and, microfilariae without nuclei to tip of tail. Mansonella (Esslingeria) comb. n., to accommodate those species with the following characters: cephalic extremity with lateral orientation; male tail flattened dorsoventrally at tip or not; vulva in midesophageal region; and, microfilariae with nuclei to tip of tail. Type species is M. (E.) perstans. Mansonella (Tetrapetalonema) comb. n., to accommodate those species with the following characters: cephalic extremity with dorsoventral orientation or with body constricted to form cephalic extremity in shape of hemisphere narrower than body behind it; male tail not flattened at tip; vulva in midesophageal region; and, microfilariae with nuclei to tip of tail. Type species is M. (T.) marmosetae. Mansonella (Sandnema) comb. n., to accommodate those species with the following characters: cephalic extremity rounded, not oriented along lateral or median axis; tip of male tail not flattened; caudal papillae on male tail not clustered around cloaca; vulva near base of esophagus; and, microfilariae with nuclei to tip of tail. Type species is M. (S.) digitata.

Mansonella ozzardi: a redescription with comments on its taxonomic relationships.

Mansonella ozzardi is redescribed from adult worms collected from the subcutaneous tissues of patas monkeys (Erythrocebus patas) infected with a Haitian strain of the filaria. The worms are small and very slender; females measure about 49 mm in length by 0.15 mm in diameter and males, 26 by 0.07 mm. Haitian (Caribbean) and Colombian (Amazon) forms of the filaria are morphologically identical, as are their microfilariae. Mansonella is most closely related to Tetrapetalonema. Based on taxonomic priority the latter becomes a synonym of Mansonella. As a consequence, T. perstans and T. streptocerca of man in Africa are designated as M. perstans (Manson, 1891) n. comb. and M. streptocerca (Macfie and Corson, 1922) n. comb. Further, M. ozzardi is most closely related to the species M. llewellyni (Price, 1962) n. comb., a parasite of the raccoon, and M. interstitium (Price, 1962) n. comb. found in squirrels, both in North America.