Evaluation of LAMP for the diagnosis of Loa loa infection in dried blood spots compared to PCR-based assays and microscopy

BACKGROUND Loa loa is a filarial species found exclusively in West and Central Africa. Microscopy is the traditional diagnosis method for human loiasis. Several molecular methods have developed as an alternative approach for identification of L. loa filarial parasites. OBJECTIVES The aim of this study was to evaluate a Loa-Loop-mediated isothermal amplification (LAMP) assay to diagnose loiasis disease on dried blood spots (DBS) samples, compared to microscopy, filaria-real time-polymerase chain reaction (PCR) and nested-Loa PCR. METHODS A total of 100 DBS samples and 100 blood smears were used for this study. DNA was extracted using saponin/Chelex method. DNA isolated was assayed by a Loa-LAMP assay in parallel to microscopy, filaria-real time PCR and nested-Loa PCR. The sensitivities and specificities of Loa-LAMP assay was computed comparing to each one of the reference methods. FINDINGS Loa-LAMP's sensitivity was more than 90% and specificity was nearly 100% when compared to molecular methods. On the other hand, sensitivity was decreased a bit when Loa-LAMP faced microscopy, but keeping the other statistical values high. MAIN CONCLUSIONS Loa-LAMP is an appropriate method for loiasis diagnosis in endemic areas. Though, it has disadvantages like the reagents' high price at the moment and not to be able to detect more filarial species at once.

An adult worm in the eye.

We report a case of ocular loiasis in a 9 yrs old girl. Very few case reports of ocular loiasis have published from India to date. Loa loa is a subcutaneous filarial parasite of man and known to be transmitted to humans by Chrysops flies. Patient presented with visual disturbances due to worm in her eye. A live adult worm was extracted and identity was confirmed by gross and microscopic examination to be Loa loa. Patient was treated with albendazole, gentamicin and steroids.

Identification and immunogenicity analysis of predominant T-B combined antigenic epitopes on the ;outer membrane protein Loa22 of Leptospira interrogans strains / 中华微生物学和免疫学杂志

Objective To screen and identify the predominant T-and B-cell ( T-B) combined an-tigenic epitopes on the outer membrane protein Loa22 of pathogenic Leptospira interrogans ( L.interrogans) stains and to further analyze their immunogenicity.Methods PCR analysis was used to detect loa22 gene in L.interrogans strains belonging to eight different serogroups or serovars prevalent in China.The PCR prod-ucts were sequenced after T-A cloning.A prokaryotic expression system for loa22 gene of L.interrogans sero-group Icterohaemorrhagiae serovar Lai strain Lai was constructed.The expressed recombinant protein rLoa22 was extracted by Ni-NTA affinity chromatography.The rabbit anti-rLoa22 serum samples and IgG were pre-pared.The T-B combined antigenic epitopes on Loa22 protein were predicted by using professional bioinfor-matic softwares.Phage display in combination with Western blot assay and ELISA were performed to identify the immunogenicity of the recombinant phage PⅢ protein-displayed and artificially-synthesized T-B com-bined antigenic epitopes, respectively.MTS assay and ELISA were performed to detect the activation of T cells and the expression of IL-2, IL-4 and IFN-γinduced by T-B combined antigenic epitopes, respectively. Results All of the tested pathogenic Leptospira strains were positive for loa22 gene, sharing 85.5%-99.8%homologies in nucleotide sequences and 93.9%-99.5%homologies in amino acid sequences.The construc-ted prokaryotic expression system for loa22 gene efficiently expressed the rLoa22 protein.Among four T-B combined antigenic epitopes (Loa22-77, Loa22-90, Loa22-125 and Loa22-157), only Loa22-90 epitope presented a strong positive band in Western blot analysis.The proliferation of CD4+T cells and the expres-sion of IL-2 ( Th1 ) and IL-4 ( Th2 ) were significantly enhanced by the stimulation with Loa22-90 epitope peptide (P<0.05).Conclusion Loa22 protein is a sequence-conserved genus-specific outer membrane protein of L.interrogans.The Loa22-90 epitope is the predominant T-B combined antigenic epitope of Loa22 protein, which might be used as a candidate antigenic epitope in the development of multiple antigenic pep-tide ( MAP) vaccines against Leptospira infection.

Comportamiento clínico, epidemiológico y microbiológico de las filariosis en la población de Mouila en Gabón / Clinical, epidemiological and microbiological behavior of filariases in the population of Mouila, Gabon

Introducción: las filarias son nematodos pertenecientes a la familia Filariidae, aunque existen alrededor de 200 filarias parasitas, solo unas pocas parasitan al hombre. Objetivos: realizar una breve descripción de estas parasitosis, que sirviera como guía al gran número de médicos cubanos colaboradores en países africanos, donde es particularmente frecuente este padecimiento, así como describir el comportamiento de las infecciones por filarias en pacientes atendidos en el Hospital Regional de Mouila, Gabón. Métodos: se realizó un estudio observacional, descriptivo, de corte transversal. Se incluyeron 87 pacientes de los 2 sexos, de 15 años de edad y más, en los que se logró confirmar algún tipo de filariosis. Resultados: se observó que 3,7 por ciento de los pacientes presentó una filariosis, 93,1 por ciento por Loa loa, 5,7 por ciento por Mansonella perstans y 1,1 por ciento por coinfección de ambas. El grupo de más de 65 años y el sexo femenino resultaron los más afectados. El síntoma más frecuente fue el prurito (59,8 por ciento), seguido por la poliartralgia, el dolor lumbar y la astenia. La eosinofilia se apreció en 100 por ciento y la anemia fue más frecuente en pacientes parasitados con Mansonella perstans. La intensidad de la infección para ambos tipos de filarias fue baja. En 86,1 por ciento de los pacientes tratados con dietilcarbamazina y 82,4 por ciento de los tratados con ivermectina, la respuesta fue satisfactoria. Conclusiones: Loa loa predominó, sobre todo en mujeres; el prurito, la anemia y la eosinofilia fueron las manifestaciones principales, la respuesta tratamiento con ivermectina mostró ventajas

Introduction: filariae are nematodes from the family Filariidae. There are about 200 parasitic filariae, but only a few infect humans. Objectives: make a brief description of these parasitic diseases which may serve as guidance to the large number of Cuban cooperation doctors in African countries, where this condition is particularly common, and describe the behavior of filarial infections in patients cared for at Mouila Regional Hospital in Gabon. Methods: a cross-sectional observational descriptive study was conducted of 87 patients of both sexes aged 15 and over with confirmed filariasis. Results: it was found that 3.7 percent of patients had some kind of filariasis: 93.1 percent due to Loa loa, 5.7 percent due to Mansonella perstans and 1.1 percent due to coinfection by both. Females and persons over 65 were the most affected groups. The most common symptom was pruritus (59.8 percent), followed by polyarthralgia, lumbar pain and asthenia. Eosinophilia was present in 100 percent of subjects, and anemia was more frequent in patients infected with Mansonella perstans. Infection intensity was low in both filariases. The response was satisfactory in 86.1 percent of the patients treated with diethylcarbamazine and 82.4 percent of those treated with ivermectin. Conclusions: Loa loa was predominant mainly among women. Pruritus, anemia and eosinophilia were the main manifestations. Treatment with ivermectin was found to be effective

Subconjunctival Loa loa worm: first case report in Brazil / Verme subconjuntival da espécie Loa loa: primeiro caso no Brasil

We report the first case of ocular infestation by Loa loa in Brazil. Loiasis is caused by infestation with Loa loa, a filarial parasite originally found in the rainforests of western and central Africa. It is transmitted by the bite of the fly Chrysops and has been recently described in other places other than Africa, in African immigrants or travellers. Our case is a 33 year-old woman from Cameroon who was living in São Paulo, Brazil, for 5 years. She was asymptomatic until one morning she started feeling "something moving" in the left eye. Under topical anesthesia, on the slit lamp, a moving worm was removed from the subconjunctival space, which later was confirmed to be a male Loa loa adult specimen. Blood tests revealed microfilaraemia of 129 mf/mL. The patient was treated with 400 mg oral albendazole for 3 weeks and 60 mg prednisone. This report illustrates an unusual ocular disease, which is extremely rare outside of Africa, but easily diagnosed and treated. Ophthalmologists should be aware of it, in face of an increasingly globalized world.

Este é o primeiro relato na literatura nacional e internacional de infestação ocular por Loa loa no Brasil. A loíase é uma filariose causada pelo parasita Loa loa, encontrado nas florestas tropicais da África equatorial. A transmissão se dá pela picada do mosquito Chrysops e casos têm sido descritos em países não africanos, em imigrantes e viajantes. O presente caso trata-se de uma paciente de 33 anos natural de Camarões e residente em São Paulo, Brasil, há 5 anos. Até então assintomática, uma manhã sentiu algo "se mexendo" em seu olho esquerdo. Sob anestesia tópica, na lâmpada de fenda, um verme altamente móvel foi removido do espaço subconjuntival e enviado para identificação, que confirmou tratar-se de um espécime macho adulto de Loa loa. Testes sanguíneos revelaram microfilaremia de 129 mf/mL. A paciente foi tratada com albendazol 400 mg e prednisona 60 mg esquema regressivo por 3 semanas. Este relato ilustra uma doença excepcionalmente rara no Brasil, e praticamente desconhecida dos oftalmologistas em nosso país.

A historical note on an imported case of loiasis in Rio de Janeiro, Brazil, 1964 / Nota histórica sobre caso importado de loíase no Rio de Janeiro, Brasil, 1964

Loiasis is a filarial disease transmitted by the Chrysops spp. tabanid flies in West and Central Africa. It is most commonly diagnosed by the clinical manifestations of Calabar swellings (transient localized inflammatory edema) or, most dramatically, by the appearance of a migrating worm through the conjunctival tissues or the bridge of the nose. We report the case of a 35-year-old resident in the city of Rio de Janeiro who displayed a moving Loa loa in the bulbar conjunctival tissue two years after returning from a six-month trip to Uganda. Surgical removal of the worm was performed.

A loaíase é uma filaríase transmitida por tabanídeos (mutucas) do gênero Chrysops na África central e ocidental, comumente diagnosticada pela apresentação clínica de edema de Calabar (edema inflamatório transitório e localizado) ou, mais dramaticamente, pela migração de um verme adulto pelo tecido conjuntival ou asa do nariz. Descrevemos o caso clínico de um paciente do sexo masculino, 35 anos, residente no Rio de Janeiro, que se apresentou com um verme adulto de Loa loa migrando sobre o tecido conjuntival bulbar dois anos após retornar de uma viagem de seis meses de duração a Uganda. Procedeu-se a remoção cirúrgica do verme.

Adverse reactions from community directed treatment with ivermectin (CDTI ) for onchocerciasis and loiasis in Ondo State, Nigeria

Onchocerciasis is an endemic disease in Ondo state, Nigeria. Community directed distribution of ivermectin is currently on-going in some local government areas of the state. Randomly selected persons (2 331 males and 2 469 females) were interviewed using a modified rapid assessment procedure for Loa loa (RAPLOA) to assess community directed treatment with ivermectin. The retrospective study evaluated the coverage, impacts and adverse reactions to the drug treatment. A questionnaire was administered by house-to-house visit in six local government areas, implementing community directed treatment with ivermectin (CDTI) in this bioclimatic zone. A total of 2,398 respondents were reported to have participated in the treatment. The overall ivermectin coverage of 49.96% was recorded (range 0 - 52% in different communities). Adverse reactions from ivermectin administration were experienced in 38% of individuals. Diverse adverse reactions experienced included predominantly itching (18.50%); oedema, especially of the face and the limbs (8.2%); rashes (3.4%) and body weakness (2.4%). Expulsion of intestinal worms occurred in 0.96% of the respondents. The occurrence of adverse reactions in relation to age categories was statistically significant. Neither fatal nor severe adverse reactions were reported by respondents. Significantly, despite experienced adverse reactions, continued participation, acceptability and compliance to ivermectin treatment was expressed by the various communities. This attitude is in consonance with the African Programme for Onchocerciasis Control (APOC) objectives. Rev. Biol. Trop. 56 (4): 1635-1643. Epub 2008 December 12.

La oncocercosis es endémica en el estado Ondo, Nigeria. Se seleccionaron 4 800 personas al azar para evaluar con encuesta retrospectiva la cobertura, efectos y reacciones al tratamiento farmacológico con ivermectina administrado por la misma comunidad. La cobertura global de ivermectina fue 50 % con reacciones adversas en 38 % de los individuos. Estas fueron comezón picazón (18%), edema, especialmente de la cara y las extremidades (8%), erupciones cutáneas (3%) y debilidad (2%); dependieron de la edad y no hubo reacciones más graves. La expulsión de las lombrices intestinales se produjo en 96% de los encuestados. A pesar de las reacciones adversas, hubo continuidad, aceptación y cumplimiento del tratamiento con ivermectina, en consonancia con los objetivos del Programa Africano para el Control de Oncocercosis (APOC).

Subconjuctival Loa loa with Calabar Swelling

Loa loa is unique among the human filariae in that adult worms are occasionally visible during subconjuntival migration. A 29-yr-old African female student, living in Korea for the past 5 yr without ever visiting her home country, presented with acute eyelid swelling and a sensation of motion on the left eyeball. Her symptoms started one day earlier and became worse over time. Examination revealed a threadlike worm beneath the left upper bulbar conjunctiva with mild eyelid swelling as well as painless swelling of the right forearm. Upon exposure to slit-lamp illumination, a sudden movement of the worm toward the fornix was noted. After surgical extraction, parasitologic analysis confirmed the worm to be a female adult Loa loa with the vulva at the extreme anterior end. On blood smear, the microfilariae had characteristic features of Loa loa, including sheath and body nuclei up to the tip of the tail. The patient also showed eosinophilia (37%) measuring 4,100/microliter. She took ivermectin (200 microgram/kg) as a single dose and suffered from a mild fever and chills for one day. This patient, to the best of our knowledge, is the first case of subconjunctival loiasis with Calabar swelling in Korea.