Molecular detection of Mansonella mariae incriminates Simulium oyapockense as a potentially important bridge vector for Amazon-region zoonoses.

OBJECTIVE: To assess the emergent zoonotic disease risk posed by the voracious human-biting blackfly species Simulium oyapockense in the peripheral regions of an expanding urban centre situated deep in the Brazilian Amazon rainforest. METHODS: We performed nine human landing catches at three periurban sites surrounding the Brazilian Amazon town of São Gabriel da Cachoeira. Using the detection of non-human primate filarial parasites as an indicator of the zoonotic disease threat posed by a biting insect, we screened 3328 S. oyapockense blackflies for the presence of zoonotic filarial DNA with an ITS-1 PCR assay and Sanger sequencing. RESULTS: Between 98 and 100% of the biting insects captured during our nine collections were identified as S. oyapockense; at our three collection sites and during our three seasonally-distinct collections this species was captured at rates between 28 and 294 blackflies per hour. PCR screening of the march-collected S. oyapockense detected infectious-stage (L3) Mansonella mariae parasites (which are only known to infect non-human primates) in >0.15% of the tested head samples. CONCLUSIONS: Our results show that residents of the periurban regions of São Gabriel da Cachoeira are routinely exposed to the bites of S. oyapockense blackflies which have previously fed on non-human primates.

Update on the biology and ecology of Culicoides species in the South-West region of Cameroon with implications on the transmission of Mansonella perstans.

BACKGROUND: Culicoides (Diptera; Ceratoponidae) are tiny, stout, blood-sucking flies with a near worldwide distribution. When present, they are often considered a biting nuisance but in addition, they are involved in the transmission of pathogens to humans, domestic and wild animals. Data on Culicoides species in the South-West region of Cameroon dates back to the 1950s. Over the decades, ecological transformation due to agriculture and deforestation may have affected the population dynamics of Culicoides and therefore our study provides an update of their bio-ecology in the region. Furthermore, the role of various Culicoides species in the transmission of parasitic filariae of the genus Mansonella remains inconclusive in this region. This study was designed to address these unknown issues and expand on current scientific knowledge. RESULTS: Eight species of Culicoides (C. bedfordi, C. inornatipennis, C. fulvithorax, C. grahamii, C. imicola, C. milnei, C. neavei and C. kumbaensis) were collected using light traps and human baits. Culicoides grahamii was the most abundant species, followed closely by C. milnei. Three species (C. milnei, C. grahamii and C. inornatipennis) were common in all observed larval development sites. Only four species (C. inornatipennis, C. fulvithorax, C. grahamii and C. milnei) were collected on humans. Anthropophilic species were more abundant (P < 0.001) in the evening (4-7 pm) when compared to the morning collections (6-9 am). After overnight fly collections using a drop trap with a human microfilaremic donor, C. milnei emerged as the potential host for transmitting Mansonella perstans. Substantial heterogeneity was observed between the trap visiting cycles of the various species (P < 0.001). The biting cycle of the main vector, C. milnei, showed two peaks (10-11 pm and 4-5 am), the highest being 10-11 pm. CONCLUSIONS: The Culicoides fauna of the South-West region of Cameroon has not changed significantly since the 1950s. Culicoides milnei was demonstrated to be the major vector of M. perstans in this part of Cameroon. It is essentially a nocturnal species which peaks in abundance between 10 and 11 pm.

High Prevalence of Mansonella perstans Filariasis in Rural Senegal.

Large parts of African and American countries are colonized by Mansonella, a very common but poorly described filarial nematode. Bloodsucking flies of the genus Culicoides are suspected to be the vector of Mansonella perstans, but no study in Senegal has confirmed that Culicoides can transmit the parasite. Designed specific real-time quantitative polymerase chain reaction (qPCR) can be used to identify microfilaria in stained blood smears. This study was performed in July and December 2010 in the southeastern Senegal, which is known to be endemic for M. perstans. We analyzed 297 blood smears from febrile and afebrile resident people by qPCR. The global prevalence of M. perstans was approximately 14.5% in both febrile and afebrile individuals. The age group of > 30 years had the highest prevalence (22.0%). No Culicoides among 1,159 studied specimens was positive for M. perstans and its vector in Senegal still requires identification.

Mansonelliasis, a neglected parasitic disease in Haiti.

Reported in Haiti as early as 1923, Mansonella ozzardi is still a neglected disease ignored by the health authorities of the country. This review is an update on the geographic distribution of the coastal foci of mansonelliasis in Haiti, the epidemiological profile and prevalence rates of microfilariae in people living in endemic areas, the clinical impact of the parasite on health and the efficiency of the transmission of the parasite among three Culicoides biting-midge species identified as vectors in Haiti. Additionally, interest in establishing a treatment programme to combat this parasite using a single dose of ivermectin is emphasised.

Mansonelliasis, a neglected parasitic disease in Haiti

Reported in Haiti as early as 1923, Mansonella ozzardi is still a neglected disease ignored by the health authorities of the country. This review is an update on the geographic distribution of the coastal foci of mansonelliasis in Haiti, the epidemiological profile and prevalence rates of microfilariae in people living in endemic areas, the clinical impact of the parasite on health and the efficiency of the transmission of the parasite among three Culicoides biting-midge species identified as vectors in Haiti. Additionally, interest in establishing a treatment programme to combat this parasite using a single dose of ivermectin is emphasised.

New records of Mansonella ozzardi: a parasite that is spreading from the state of Amazonas to previously uninfected areas of the state of Acre in the Purus River region

Mansonella ozzardi infections are common in the riverside communities along the Solimões, Negro and Purus Rivers in the state of Amazonas (AM). However, little is known about the presence of this parasite in communities located in regions bordering AM and the state of Acre. The prevalence rate of M. ozzardi infections was determined in blood samples from volunteers according to the Knott method. A total of 355 volunteers from six riverine communities were enrolled in the study and 65 (18.3%) were found to be infected with M. ozzardi. As expected, most of the infections (25%) occurred in individuals involved in agriculture, cattle rearing and fishing and an age/sex group analysis revealed that the prevalence increased beginning in the 40-50-years-of-age group and reached 33% in both sexes in individuals over 50 years of age. Based on the described symptomatology, articular pain and headache were found to be significantly higher among infected individuals (56 and 65% prevalence, respectively, p < 0.05). Sera from volunteers were subjected to ELISA using a cocktail of recombinant proteins from Onchocerca volvulus to evaluate the specificity of the test in an endemic M. ozzardi region. No cross-reactions between M. ozzardi-infected individuals and recombinant O. volvulus proteins were detected, thus providing information on the secure use of this particular cocktail in areas where these parasites are sympatric.

New records of Mansonella ozzardi: a parasite that is spreading from the state of Amazonas to previously uninfected areas of the state of Acre in the Purus River region.

Mansonella ozzardi infections are common in the riverside communities along the Solimões, Negro and Purus Rivers in the state of Amazonas (AM). However, little is known about the presence of this parasite in communities located in regions bordering AM and the state of Acre. The prevalence rate of M. ozzardi infections was determined in blood samples from volunteers according to the Knott method. A total of 355 volunteers from six riverine communities were enrolled in the study and 65 (18.3%) were found to be infected with M. ozzardi. As expected, most of the infections (25%) occurred in individuals involved in agriculture, cattle rearing and fishing and an age/sex group analysis revealed that the prevalence increased beginning in the 40-50-years-of-age group and reached 33% in both sexes in individuals over 50 years of age. Based on the described symptomatology, articular pain and headache were found to be significantly higher among infected individuals (56 and 65% prevalence, respectively, p < 0.05). Sera from volunteers were subjected to ELISA using a cocktail of recombinant proteins from Onchocerca volvulus to evaluate the specificity of the test in an endemic M. ozzardi region. No cross-reactions between M. ozzardi-infected individuals and recombinant O. volvulus proteins were detected, thus providing information on the secure use of this particular cocktail in areas where these parasites are sympatric.

[Occurrence of Mansonella ozzardi (Nematoda, Onchocercidae) in riverine communities of the Purus river, Boca do Acre municipality, Amazonas State, Brazil]. / Ocorrência da Mansonella ozzardi (Nematoda, Onchocercidae) em comunidades ribeirinhas do rio Purus, Município de Boca do Acre, Amazonas, Brasil.

The study aimed to estimate the prevalence of Mansonella ozzardi and calculate the parasitic infection rate in simuliid blackflies. The research was conducted in communities on the Purus River, Boca do Acre municipality, Amazonas State, Brazil. Prevalence was measured using the thick smear method. Captured blackflies were dissected to verify the parasitic infection rate. M. ozzardi prevalence was 27.30% (77/282). The study showed higher prevalence in men (31.97%) than women (22.22%), farmers (48.99%), and individuals in the 38-47 (60.00%), 48-57 (66.66%), and 58-67-year age brackets (75.00%). Microfilaremia was higher in individuals 58 to 67 years of age (average= 58.41 mf/40 microl), men (41.44 mf/40 microl), and farmers (49.94 mf/40 microl). Only the simuliid Cerqueirellum amazonicum was found infected with a parasitic infection rate of 0.98%.

Ocorrência da Mansonella ozzardi (Nematoda, Onchocercidae) em comunidades ribeirinhas do rio Purus, Município de Boca do Acre, Amazonas, Brasil / Occurrence of Mansonella ozzardi (Nematoda, Onchocercidae) in riverine communities of the Purus river, Boca do Acre municipality, Amazonas State, Brazil

Este estudo teve o objetivo de estimar as prevalências de Mansonella ozzardi e calcular taxa de infecção parasitária nos simulídeos. O trabalho foi realizado em comunidades ribeirinhas do rio Purus, Boca do Acre, Amazonas, Brasil. As prevalências foram obtidas por meio do método de gota espessa de sangue obtido por porção digital. Os simulídeos coletados foram dissecados para estimar a taxa de infecção parasitária. A prevalência de M. ozzardi foi de 27,3 por cento (282/77). Foram observadas maiores prevalências nos homens (31,97 por cento) que nas mulheres (22,22 por cento), nos agricultores (48 por cento) e nos indivíduos entre: 38-47 (60 por cento), 48-57 (66,66 por cento) e 58-67 (75 por cento). A microfilaremia foi maior nos indivíduos entre 58-67 anos (média = 58,41mf/40µL), sexo masculino (41,44mf/40µL) e nos agricultores (49,94mf/40µL). Somente o simulídeo Cerqueirellum amazonicum foi encontrado infectado com taxa de infecção parasitária de 0,98 por cento.

The study aimed to estimate the prevalence of Mansonella ozzardi and calculate the parasitic infection rate in simuliid blackflies. The research was conducted in communities on the Purus River, Boca do Acre municipality, Amazonas State, Brazil. Prevalence was measured using the thick smear method. Captured blackflies were dissected to verify the parasitic infection rate. M. ozzardi prevalence was 27.30 percent (77/282). The study showed higher prevalence in men (31.97 percent) than women (22.22 percent), farmers (48.99 percent), and individuals in the 38-47 (60.00 percent), 48-57 (66.66 percent), and 58-67-year age brackets (75.00 percent). Microfilaremia was higher in individuals 58 to 67 years of age (average= 58.41mf/40µl), men (41.44mf/40µl), and farmers (49.94mf/40µl). Only the simuliid Cerqueirellum amazonicum was found infected with a parasitic infection rate of 0.98 percent.

[Mansonella perstans filariasis]. / La filariosi da Mansonella perstans.

Mansonella perstans filariasis is widely present in Africa and equatorial America and its pathogenicity has been recently reconsidered. Although M. perstans infection has been considered a minor filariasis, remaining asymptomatic in most of infected subjects, more recent studies have shown that M. perstans is capable of inducing a variety of clinical features, including angioedemas, swellings like the "Calabar swellings" of loiasis, pruritus, fever, headache, pain in bursae and/or joint synovia, or in serous cavities. It is likely that some of the pathological changes observed are induced by the immune response to the infection. Eosinophilia is present in many cases of infection. Moreover M. perstans filariasis is difficult to be treated. Effective treatment is lacking and there is no consensus on optimal therapeutic approach. The most commonly used drug is diethylcarbamazine (DEC) that is however often ineffective. Although other drugs have been tried (e.g. praziquantel, ivermectin), none has proven to be reliably and rapidly effective. Mebendazole seemed more active than DEC in eliminating the infection, with a comparable rate of overall responses. Thiabendazole evidenced a small, but significant activity against the infection. Combination treatments (DEC plus mebendazole) resulted in a significantly higher activity compared with the single drugs.

Biting of anthropophilic Culicoides fulvithorax (Diptera: Ceratopogonidae), a vector of Mansonella perstans in Nigeria.

Anthropophilic Culicoides were investigated in a rural community endemic for Mansonella perstans in Ijebu North area of western Nigeria between December 2003 and October 2004. Three hundred and fifty-nine adults of Culicoides fulvithorax collected by human bait in the morning were dissected for Mansonella perstans larvae, and 1.95% of infection rate was found. Seasonal abundance of C. fulvithorax was investigated by monthly biting rates, and showed that higher prevalence was observed in rainy season, with peak in September. Culicoides prevalence was positively correlated with rainfall and relative humidity, but not temperature. Human perceptions on the behavior of these biting midges were determined by interviewing 854 self-selected villagers, of which 86.5% of the interviewees confessed having experienced Culicoides bites. Between 76.5 and 99.1% of the various age groups complained body reactions to Culicoides bites. Itching was the most frequent body reaction. No interviewees associated Culicoides with transmission of any parasitic infections. The results showed need to adequately control Culicoides in the community.

Biting of anthropophilic Culicoides fulvithorax (Diptera: Ceratopogonidae), a vector of Mansonella perstans in Nigeria

Anthropophilic Culicoides were investigated in a rural community endemic for Mansonella perstans in Ijebu North area of western Nigeria between December 2003 and October 2004. Three hundred and fifty-nine adults of Culicoides fulvithorax collected by human bait in the morning were dissected for Mansonella perstans larvae, and 1.95% of infection rate was found. Seasonal abundance of C. fulvithorax was investigated by monthly biting rates, and showed that higher prevalence was observed in rainy season, with peak in September. Culicoides prevalence was positively correlated with rainfall and relative humidity, but not temperature. Human perceptions on the behavior of these biting midges were determined by interviewing 854 self-selected villagers, of which 86.5% of the interviewees confessed having experienced Culicoides bites. Between 76.5 and 99.1% of the various age groups complained body reactions to Culicoides bites. Itching was the most frequent body reaction. No interviewees associated Culicoides with transmission of any parasitic infections. The results showed need to adequately control Culicoides in the community.

Transfusional Mansonella perstans microfilariasis.

Mansonella perstans filariasis is widely distributed across the center of Africa and equatorial America. We describe a case of post-transfusional M. perstans microfilariasis in a young child, affected with severe Plasmodium falciparum malaria, admitted in Goundi Hospital in South of Chad. A decrease of M. perstans microfilariasis in the patient's blood was observed, with no subsequent development of either clinical symptoms or eosinophilia. We suggest that, in endemic areas, transfused M. perstans microfilariae may be cleared from the blood over relatively short periods of time. It is likely that only adult worms are responsible for symptoms and eosinophilia, whereas microfilariae in the bloodstream are unable to give clinical manifestations.

Congenital intracranial filariasis: a case report.

We present the case of a newborn with intracranial extra-axial collections which mere partially calcified. The underlying cause was shown to be filariasis which had been transmitted from the mother.

Epidemiology of Mansonella perstans filariasis in the forest region of south Congo.

A study of Mansonella perstans filariasis conducted in the Chaillu mountains, Southern Congo, showed that 108 of 134 Pygmies (80.6%) and 79 of 302 Bantus (26.2%) presented with microfilaraemia. The mean microfilarial densities were also significantly higher in the Pygmies (1213 ml-1 of blood) than in the Bantus (136 ml-1). Ninety eight per cent of the Culicoides taken which had bitten man in the daytime were C. grahamii, and 0.8% of these were infected with filarial larvae. Two other species of Culicoides (C. kumbaensis and C. rutshuruensis) might also play a role in the transmission of M. perstans.

Revisión de la familia simuliidae (Diptera, Nematocera) en Venezuela / Review of the simuliidae family (Diptera, Nematocera) in Venezuela

En la presente revisión, se hace una exposición cronológica de los estudios sobre taxonomía y sistemática de simúlidos que se han llavado a cabo hasta el presente en Venesuela. Se acompaña un mapa indicando la distribución geográfica de los vectores y fondos de oncocercosis y mansonelosis en el país. Del género Simulium Latreille, 1902, se sañalan 51 especies y 7 del género Gigantodax Enderlein, 1925. Se presenta una lista sobre la distribución geográfica por entidades de las 59 especies de la familia Simuliidae Schiner, 1864, sañalando un total de 14 sinonimos en Venezuela