Drivers of flea (Siphonaptera) community structure in sympatric wild carnivores in northwestern Mexico.

Host identity, habitat type, season, and interspecific interactions were investigated as determinants of the community structure of fleas on wild carnivores in northwestern Mexico. A total of 540 fleas belonging to seven species was collected from 64 wild carnivores belonging to eight species. We found that the abundances of some flea species are explained by season and host identity. Pulex irritans and Echidnophaga gallinacea abundances were significantly higher in spring than in fall season. Flea communities on carnivore hosts revealed three clusters with a high degree of similarity within each group that was explained by the flea dominance of E. gallinacea, P. simulans, and P. irritans across host identity. Flea abundances did not differ statistically among habitat types. Finally, we found a negative correlation between the abundances of three flea species within wild carnivore hosts. Individual hosts with high loads of P. simulans males usually had significantly lower loads of P. irritans males or tend to have lower loads of E. gallinacea fleas and vice-versa. Additionally, the logistic regression model showed that the presence of P. simulans males is more likely to occur in wild carnivore hosts in which P. irritans males are absent and vice-versa. These results suggest that there is an apparent competitive exclusion among fleas on wild carnivores. The study of flea community structure on wild carnivores is important to identify the potential flea vectors for infectious diseases and provide information needed to design programs for human health and wildlife conservation.

[Description of Trochilopsylla torresmurai n. gen., n. sp. (Siphonaptera: Ceratophyllidae) from Chile, the first flea known to parasitize a humming bird (Aves: Trochilidae)]. / Description de Trochilopsylia torresmurai n. gen., n. sp. (Siphonaptera : Ceratophyllidae) du Chiu, première mention d'une puce parasite d'oiseau-mouche (Aves : Trochiudae).

A new genus and a new species are described from fleas of occupied nest from humming bird, Oreotrichulus estella (d'Orbigny & Lafresnaye, 1838). This taxa shows, in particular, some affinities with Dasypsyllus Baker, 1908, parasite on birds, cosmopolitan except in afrotropical and austral regions, and Smitipsylla Lewis, 1971, parasite on flying squirrels (Anomaluridae) in oriental region.

Tungiasis--a cause of painful feet in a tropical traveller.

Tungiasis is an ectoparasitosis caused by the impregnated female sand flea Tunga penetrans. It is endemic in certain resource poor areas around the world and imported infestations in travellers can lead to considerable morbidity. With the rise in international travel and immigration, the likelihood of physicians encountering such tropical skin infestations is rising. The ability of physicians to recognise tungiasis early will be immensely beneficial to patients. We describe a case of tungiasis where a traveller presented with painful foot lesions. The patient had returned to the United Kingdom 4 days previously after spending 4 weeks in the Pantanal region in Brazil. A literature review on this subject was undertaken in this article.

Investigação do papel de vetores secundários da Leishmania (Leishmania) infantum no Município de Mirandópolis, SP, Brasil / Investigation of the role of secondary vectors of Leishmania (Leishmania) infantum in the City of Mirandópolis, SP, Brazil

Introdução. A leishmaniose visceral (LV) vem se apresentando como grave problema de saúde pública na região noroeste do Estado de São Paulo, desde o final da década de 90 e o flebotomíneo Lutzomyia longipalpis, reconhecido vetor da Leishmania (Leishmania) infantum agente etiológico dessa enfermidade, tem sido encontrado nos diversos municípios com transmissão dessa parasitose. Porém, em estudo realizado em 2004/2005 no município de Mirandópolis, localizado nesta região, este díptero foi encontrado em baixíssima freqüência, e por outro lado, observou-se uma soro-prevalência elevada, para leishmaniose visceral, em cães (60,8 por cento), sugerindo que a maciça infecção na população canina antecedeu ao período deste estudo ou outros mecanismos de transmissão poderiam estar atuando. Dentre os possíveis mecanismos de transmissão, os envolvendo carrapatos e pulgas merecem especial atenção devido à alta freqüência e intimidade com que são observados nos cães. Objetivo. O presente estudo teve como objetivo avaliar a importância de ixodídeos e sifonápteros na transmissão e manutenção da leishmaniose visceral canina (LVC). Método: Dos cães recolhidos ao Centro de Controle de Zoonoses do município de Mirandópolis, no período de agosto/200? a maio/2008, depois de identificados por sexo, idade e condição clínica (assintomáticos, oligossintomáticos ou sintomáticos) e sacrificados de forma humanitária, coletou-se sangue, fragmento de Iinfonodo poplíteo e quando presentes, carrapatos e pulgas. Os ectoparasitos foram então separados por grupos taxonômicos e identificados quanto à espécie, sexo e fase de desenvolvimento, no caso dos carrapatos. Foi realizado ensaio de imunoadsorção ligado à enzima (ELlSA) e reação da polimerase em cadeia (PCR) nas amostras obtidas dos cães e os ectoparasitas deles colhidos foram submetidos à PCR.Os resultados foram analisados pelos testes estatísticos: Indice de correlação de Pearson e Probit...

Tunga penetrans: a stowaway from around the world.

Tungiasis is a cutaneous ectoparasitic infestation by the female sand flea Tunga penetrans. It is predominantly a health problem in sub-Saharan Africa, the Caribbean, Latin America and South America. However, increasing numbers of returning travellers, immigrants, and adopted children are also affected in non-tropical countries. It is a cause of substantial morbidity, with prevalence rates as high as 76% in certain endemic areas. To date, the early extraction of the flea is still the first line therapy.

Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil. V. Cytokine concentrations in experimentally infected Wistar rats.

Tungiasis is caused by the penetration of the female sand flea Tunga penetrans into the skin of its host. This parasitic skin disease is almost invariably associated with an intense inflammation around embedded fleas, the underlying mechanisms being unknown. A study was undertaken to determine whether Wistar rats can be used as an animal model to assess cytokine kinetics during the natural course of the infection. Laboratory-raised Wistar rats were exposed in cages put on the soil in an area with high human attack rates. Rats were examined daily and blood samples were taken before exposure and at 2, 6, 10, 13, 16 and 20 days after flea penetration. TNF-alpha, IL-1 beta, IFN-gamma, IL-4, IL-10 and CINC (a rat cytokine- induced neutrophil chemoattractant and member of the IL-8 family) were determined by enzyme immunoassay. The results showed an increasing serum concentration of TNF-alpha and IL-1 beta 10-13 days after penetration and a rapid increase in IL-4 2 days after fleas became embedded. During the natural course of the infection, the ratio of the serum concentration of TNF-alpha to that of IL-10 decreased, indicating a relative increase in the secretion of the anti-inflammatory cytokine. The treatment of lesions with silicone oil abrogated the natural disease course and changed the pattern of cytokine secretion. We conclude that the Wistar rat is an appropriate model to study immune responses in tungiasis.

The Eyam plague revisited: did the village isolation change transmission from fleas to pulmonary?

Back in the 17th century the Derbyshire village of Eyam fell victim to the Black Death, which is thought to have arrived from London in some old clothes brought by a travelling tailor. The village population was 350 at the commencement of plague, of which only 83 survived. Led by the church leaders, the village community realized that the whole surrounding region was at risk from the epidemic, and therefore decided to seal themselves off from the other surrounding villages. In the first 275 days of the outbreak, transmission was predominantly from infected fleas to susceptible humans. From then onward, mortality sharply increased, which indicates a changing in transmission pattern. We hypothesize that the confinement facilitated the spread of the infection by increasing the contact rate through direct transmission among humans. This would be more consistent with pulmonary plague, a deadlier form of the disease. In order to test the above hypothesis we designed a mathematical model for plague dynamics, incorporating both the indirect (fleas-rats-humans) and direct (human-to-human) transmissions of the infection. Our results show remarkable agreement between data and the model, lending support to our hypotheses. The Eyam plague episode is celebrated as a remarkable act of collective self-sacrifice. However, to the best of our knowledge, there were no evidence before that the confinement actually increased the burden payed by the commoners. In the light of our results, it can be said that the hypothesis that confinement facilitated the spread of the infection by increasing the contact rate through direct transmission is plausible.

Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil: IV. Clinical and histopathology.

Tungiasis is a parasitic skin disease caused by the sand flea Tunga penetrans. This ectoparasitosis is endemic in South America, the Caribbean and sub-Saharan Africa, where it is an important but neglected health problem in resource-poor communities. As part of a study of tungiasis-related morbidity in a typical slum in Fortaleza, Brazil, we identified 86 individuals with tungiasis. Lesions were counted, classified according to the stage of development, and clinical pathology was documented. One hundred and nine lesions were biopsied and examined by histological sectioning. The patients had between 1 and 145 lesions (median 14.5), the majority occurring in clusters. In all, 77% of patients reported severe pain at the site of the lesion, and 52% had one or more nails lost or severely deformed. Intense inflammation and/or fissures hindered 45% of the patients from walking normally. Signs of superinfection were observed in 29%, and signs of generalized inflammation in 2% of patients. Clinical pathology was significantly related to the number of lesions, and the total number of parasites present correlated with the number of fleas occurring in clusters. Clinical pathology was frequently accompanied by a pathological alteration of the epidermis (predominantly hyperplasia, parakeratosis, hyperkeratosis, and spongiosis) and the dermis. Tungiasis causes a broad spectrum of clinical histopathological alterations, and is a serious health threat in a typical, impoverished community in northeast Brazil. The clinical pathology is closely related to the parasite burden of an individual and the clustering of embedded fleas at certain predilection sites.

Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil: III. Cytokine levels in peripheral blood of infected humans.

Tungiasis is caused by penetration of the female jigger flea, Tunga penetrans, into the skin of its host. This parasitic skin disease is almost invariably associated with intense inflammation around embedded fleas, the underlying mechanisms being unknown. A study was undertaken to determine whether the inflammatory process can be attributed to immune activation induced by a biologically active foreign body. We determined the concentrations of Th1-mediated (IFN-gamma, TNF-alpha) and Th2-mediated (IL-4) cytokines in the sera of patients with tungiasis. The results were compared with those of controls infected with different helminths or exposed to soil-transmitted helminths. The results show that tungiasis causes a mixed Th1 and Th2 immune response, characterized by significantly increased concentrations of the pro-inflammatory cytokines IFN-gamma and TNF-alpha, with a slightly increased concentration of IL-4. The preponderance of the Th1 immune response was indicated by a significantly increased TNF-alpha/IL-4 ratio in patients with tungiasis, as compared with the control groups.

Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil: I. Natural history of tungiasis in man.

Tungiasis is an important health problem in poor communities in Brazil and is associated with severe morbidity, particularly in children. The causative agent, the female flea Tunga penetrans, burrows into the skin of its host, where it develops, produces eggs and eventually dies. From the beginning of the penetration to the elimination of the carcass of the ectoparasite by skin repair mechanisms, the whole process takes 4-6 weeks. The present study is based on specimens from 86 patients, for some of whom the exact time of penetration was known. Lesions were photographed, described in detail and biopsied. Biopsies were examined histologically and by means of scanning electron microscopy (SEM). Based on clinical, SEM and histological findings, the "Fortaleza classification" was elaborated. This allows the natural history of tungiasis to be divided into five stages: (1) the penetration phase, (2) the phase of beginning hypertrophy, (3) the white halo phase, (4) the involution phase and (5) residues in the host's skin. Based on morphological and functional criteria, stages 3 and 4 are divided into further substages. The proposed Fortaleza classification can be used for clinical and epidemiological purposes. It allows a more precise diagnosis, enables the assessment of chemotherapeutic approaches and helps to evaluate control measures at the community level.

Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil. II. Prevalence, parasite load and topographic distribution of lesions in the population of a traditional fishing village.

Tungiasis is hyperendemic in many poor communities in Brazil and is associated with considerable morbidity. In order to understand the factors that determine the distribution of this ectoparasitosis in a rural community, an epidemiological study was carried out in a traditional fishing village in Ceará State, north-eastern Brazil. Based on active case detection and voluntary participation, 91% of the population (belonging to 95% of all families) was examined. Embedded fleas were looked for over all parts of the body, counted, and the lesions were staged. The overall prevalence of infestation was 51.3% (95% CI: 47.0-55.5). More males than females were infested (54.8% vs 48.3%); however, this difference was not statistically significant. Age-specific prevalence rates followed an S-shaped curve with peaks in children aged 5-9 years and people elder than 60 years. The parasite burden was high (range 1-145 lesions; arithmetic mean: 8.9) and particularly elevated in males, children <15 years and the elderly. The distribution of the parasite burden was uneven within the population with the majority of the lesions in a few individuals: the 23 subjects (8% of all infested) with severe infestation (>30 lesions) accounted for 1,366 of the 2,493 lesions (54.8%) documented. The study shows that tungiasis is a highly prevalent ectoparasitosis in this deprived community with a peculiar distribution of prevalence and parasite burden.

High prevalence of tungiasis in a poor neighbourhood in Fortaleza, Northeast Brazil.

Tungiasis has been reported to occur in many Latin American, Caribbean and African countries. However, epidemiological data are still very scanty and do not exist at all for Brazil. To fill this gap, a cross-sectional study has been undertaken in a shantytown (favela) in Fortaleza, Ceará State, northeast Brazil. All 327 households of a circumscribed sub-area were visited, and 1185 out of the 1460 household members were thoroughly examined for the presence of tungiasis. Thirty-four% (95% CI: 30.9-36.4) were found to be infected with Tunga penetrans with a significant preponderance of the male sex (p<0.0001). In the children five to nine years old, the age group most heavily affected, the prevalence rate was 65.4% (95% CI: 54.0-75.7) in boys and in 48.3% (95% CI: 37.4-59.2) in girls. The data show that tungiasis is hyper-endemic in the study area. As the favela is typical for the many poor communities in northeast Brazil, it can be assumed that tungiasis is a frequent infection in the underprivileged in this part of the country.

Pulícidos: aspectos adaptativos y biológicos / Pulicides: adaptative and biological aspects

Las pulgas son insectos hematófagos que se caracterizan por una baja especificidad parasitaria. Son ectoparásitos de distintos animales y del hombre. El cuerpo de estos insectos está comprimido lateralmente y las antenas pueden replegarse dentro de un surco a los costados de la cabeza, características óptimas para un mejor desplazamiento entre los pelos y las plumas de los hospedadores. Los tres pares de patas son fuertes y poderosas, armadas con robustas espinas y en sus extremos con un par de grandes uñas en forma de garfios. El tercer par es el que está adaptado para saltar. Las piezas bucales son sucsopicadoras y modificadas en forma de estiletes. Algunas especies tienen unas hileras de cerdas (ctenidios) en la zona genal y/o en el dorso del primer segmento toráxico que evitan los movimientos de retroceso y la caída del cuerpo del hospedador. Esta característica también dificulta la extracción de los parásitos. La importancia de los pulícidos radica entre otras, por ser transmisores de la peste y el tifus. Se muestran bajo SEM y con microfotografías las adaptaciones al parasitismo, la biología y las afecciones cutáneas que se producen

Pulícidos: aspectos adaptativos y biológicos / Pulicides: adaptative and biological aspects

Las pulgas son insectos hematófagos que se caracterizan por una baja especificidad parasitaria. Son ectoparásitos de distintos animales y del hombre. El cuerpo de estos insectos está comprimido lateralmente y las antenas pueden replegarse dentro de un surco a los costados de la cabeza, características óptimas para un mejor desplazamiento entre los pelos y las plumas de los hospedadores. Los tres pares de patas son fuertes y poderosas, armadas con robustas espinas y en sus extremos con un par de grandes uñas en forma de garfios. El tercer par es el que está adaptado para saltar. Las piezas bucales son sucsopicadoras y modificadas en forma de estiletes. Algunas especies tienen unas hileras de cerdas (ctenidios) en la zona genal y/o en el dorso del primer segmento toráxico que evitan los movimientos de retroceso y la caída del cuerpo del hospedador. Esta característica también dificulta la extracción de los parásitos. La importancia de los pulícidos radica entre otras, por ser transmisores de la peste y el tifus. Se muestran bajo SEM y con microfotografías las adaptaciones al parasitismo, la biología y las afecciones cutáneas que se producen (AU)

Enfermedades cutáneas producidas por algunos artrópodos en Chile / Cutaneous diseases caused by some arthropods in Chile

Existen muchos artrópodos que afectan al hombre y a animales. Algunos artrópodos sólo producen manifestaciones cutáneas o sistémicas, otros son vectores de diversas enfermedades. Las picaduras y mordeduras de artrópodos son un motivo de consulta muy frecuente en la práctica dermatológica diaria, la mayoría de diagnóstico y tratamiento fácil, sin complicaciones. A veces, sin embargo, las manifestaciones puden ser tan greves que producen la muerte. En ocaciones, por ejemplo, en pacientes que han viajado al extranjero, el diagnóstico de las lesiones puede ser difícil, y es necesario profundizar en los diagnósticos diferenciales. En este artículo revisamos las patologías cutáneas más frecuentes producidas por distintos artrópodos de las clases Insecta y Aracnida, tales como abejas, pulgas, moscas, chinches, vinchucas, arañas y escorpiones. Se describen con detalle las distintas manifestaciones cutáneas y sistémicas y se entregan algunos elementos teóricos en el tratamiento de éstas

Tungiasis: tratamiento de un caso con invermectina / Tungiasis: case report treated with ivermectin

Se presenta un paciente con tungiasis múltiple que fue tratado con ivermectina por vía oral y se obtuvo una excelente respuesta terapéutica, sin efectos colaterales indeseables, Este fármaco hasta el momento no fue utilizado en el tratamiento de esta enfermedad. Se efetúa una revisión de la tungiasis, así como de las indicaciones y mecanismo de acción de la ivermectina

Tungiasis: tratamiento de un caso con invermectina / Tungiasis: case report treated with ivermectin

Se presenta un paciente con tungiasis múltiple que fue tratado con ivermectina por vía oral y se obtuvo una excelente respuesta terapéutica, sin efectos colaterales indeseables, Este fármaco hasta el momento no fue utilizado en el tratamiento de esta enfermedad. Se efetúa una revisión de la tungiasis, así como de las indicaciones y mecanismo de acción de la ivermectina (AU)