An allele specific PCR assay for screening for drug resistance among Wuchereria bancrofti populations in India.

Background & objectives: Albendazole, a commonly used anthelminthic drug that targets the polymerization of α- and β-tubulin dimer is currently co-administered with the antifilarial drug, diethylcarbamazine citrate (DEC) in the ongoing Global Programme for Elimination of Lymphatic Filariasis (GPELF). The experience in veterinary field has shown that there can be a rapid development of resistance to this drug, which therefore, needs to be monitored regularly in GPELF. Hence, we investigated the nucleotide polymorphism in the albendazole-binding domain of the isotype 1 β-tubulin gene from several populations of Wuchereria bancrofti and developed an AS-PCR assay useful in screening for sensitive/resistance alleles among parasite populations and also evaluated its utility. Methods: For studying the polymorphism of isotype 1 β-tubulin gene, a 475 bp fragment spanning exon 5 and 6 of the gene was amplified and sequenced from the genomic DNA of W. bancrofti collected from six geographic regions of India. An allele specific (AS) PCR for screening albendazole sensitivity/resistance was developed and a total of 55 mf samples from blood smears on slides collected from Thiruvannamalai, Thanjavur and Puducherry were screened. Selective therapy with DEC was in place in three areas, mass drug administration (MDA) with DEC alone was implemented in four areas, while DEC plus albendazole was administered in one district. Results: The analysis of the nucleotide sequence of the fragment from 20 W. bancrofti populations showed the domain to be highly conserved. An allele-specific PCR assay developed was used to detect sensitive/ resistance alleles among 55 isolates of W. bancrofti and no albendazole resistance alleles were detected among the populations tested. Interpretation & conclusion: The drug-binding domain of isotype 1 β-tubulin gene of W. bancrofti from different geographical locations was highly conserved. The AS-PCR developed showed potential application as a tool for monitoring albendazole sensitivity/resistance alleles among W. bancrofti populations, in areas where combination therapy of DEC-albendazole is being mass administered in the LF elimination programme.

Dirofilariose: zoonose emergente negligenciada: [revisão] / Dirofilariasis: neglected emerging zoonosis: [revision]

A dirofilariose é uma zoonose pouco conhecida causada por Dirofilaria spp., nematódeo mais conhecido como verme do coração dos cães (Dirofilaria immitis), parasita do sistema circulatório desses animais, mas que também pode acometer gatos e o ser humano. Sua ocorrência está intimamente ligada à presença de mosquitos vetores (Aedes spp., Anopheles spp., Culex spp.), condições climáticas favoráveis, assim como trânsito entre regiões indenes e endêmicas/epidêmicas. O ser humano pode se infectar com D. immitis (pulmão), Dirofilaria repens (pulmão, subcutâneo) e Dirofilaria tenuis (subcutâneo). A fisiopatologia está intimamente ligada à morte do parasita onde, no cão, pode induzir a obstrução de vasos circulatórios e no ser humano produzir uma lesão nodular com intensa reação inflamatória no parênquima pulmonar com formato de moeda observada nas radiografias. Pode ser diagnosticada pelo exame físico, pela detecção de microfilárias na circulação sangüínea, imunoadsorção enzimático (ELISA), alterações radiográficas, ecocardiografia, ultrassonografia e necropsia. Há riscos no tratamento, sendo a prevenção com a utilização de drogas nos animais o método mais eficaz, principalmente em visitas a áreas endêmicas ou epidêmicas, diminuindo-se, assim, o risco para saúde pública devido à disseminação do parasita.

Dirofilariasis is an unknown zoonosis, caused by Dirofilaria spp, nematodea most known as dog's heartworm (Dirofilaria immitis), which parasites the vascular system of these animals, but infects cats and human beings too. Its occurrence is highly linked to the presence of mosquitoes (Aedes spp., Anopheles spp., Culex spp.), adequate climatic conditions, as well as the transit between infection-free and endemic/epidemic regions. Human beings can be infected by D. immitis (lung), Dirofilaria repens (lung, subcutaneous) and Dirofilaria tenuis (subcutaneous). The physiopathology is highly dependent of the parasite death, inducing the obstruction of the vascular system in dogs and nodular lesions with intense inflammatory reaction in pulmonary parenchyma, like a coin lesion, observed in the radiographs. It can be diagnosed by physical examination, microfilarias detection on the vascular system, enzymatic immunoadsortion (ELISA), radiographic alterations, echocardiography, ultrasonography and necropsy. There are risks on treatment and drug prevention in animals is the most efficient method, mainly in visits to endemic or epidemic areas, decreasing the risk to public health due to the parasite dissemination.

Subperiodic, asymptomatic microfilaremia in an adult male from Mysore: a nonendemic area.

Wuchereria bancrofti is found throughout tropics and subtropics like Asia, Pacific islands, Africa, areas of South America and Caribbean basin. In all these areas, except Pacific islands, microfilaria occurs in the periodic form, in which case the microfilaria are found in large numbers in the peripheral blood during night. In the Pacific islands, they occur in the subperiodic form, i.e., microfilaria are present in the peripheral blood at all times and reach the maximum level of parasitemia in the afternoon. Microfilaria of Wuchereria bancrofti and Brugia malayi occurring in India displays a nocturnal periodicity, appearing in large numbers at night. This is the biological adaptation to the nocturnal biting habits of the vector mosquitoes. The maximum density in blood is reported between 10 PM and 2 AM. Here is a case report of asymptomatic microfilaremia showing subperiodicity, which is very unusual in India.

Successful Control of Lymphatic Filariasis in the Republic of Korea

A successful experience of lymphatic filariasis control in the Republic of Korea is briefly reviewed. Filariasis in the Republic of Korea was exclusively caused by infection with Brugia malayi. Over the past several decades from the 1950s to 2006, many investigators exerted their efforts to detection, treatment, and follow-up of filariasis patients in endemic areas, and to control filariasis. Mass, combined with selective, treatments with diethylcarbamazine to microfilaria positive persons had been made them free from microfilaremia and contributed to significant decrease of the microfilarial density in previously endemic areas. Significant decrease of microfilaria positive cases in an area influenced eventually to the endemicity of filariasis in the relevant locality. Together with remarkable economic growth followed by improvement of environmental and personal hygiene and living standards, the factors stated above have contributed to blocking the transmission cycle of B. malayi and led to disappearance of this mosquito-borne ancient disease in the Republic of Korea.

Acute eosinophilic pneumonia due to round worm infestation.

We report a case of an 18 month old child who presented with sever eosinophilic pneumonia requiring ventilation as a result of round worm infestation. This child presented with symptoms alike acute severe asthma and had high absolute eosinophil count of 9,234/cmm.A course of steroids, albendazole and diethylcarbazine were followed by rapid recovery and a decrease in eosinophil counts to 616/cmm within one month of treatment. This is the first reported case of a child with severe eosinophilic pneumonia requiring ventilation as a result of roundworm infection.

Clinico-laboratory profile of 45 filarial arthritis cases.

This prospective observational study was done during the period from January 2000 to December 2004 including 45 cases of lymphatic filariasis manifested with acute arthritis. Different investigations were carried out to exclude allergy, parasitic and infectious diseases, autoimmune disorder and malignancy. They were given standard treatment with oral non-steroidal anti-inflammatory drugs (NSAIDs). Articular symptoms were not relived satisfactorily. Later they were given oral corticosteroids. During treatment slight relief of symptoms were noted, but all sign-symptoms reappear after withdrawal of corticosteroid drugs. Treatment with oral diethylcarbamazine citrate (DEC) (150 mg/day) for 3 weeks showed complete resolution of arthritis. No side effects or relapse were encountered. The basic mechanism of relief of pain remains unknown. It was assumed that during benign course of lymphatic filariasis, development of arthritis result most likely due to reaction against some occult agents in the joints.

Filariose linfática em Belém, Estado do Pará, Norte do Brasil e a perspectiva de eliminação / Lymphatic filariasis in Belém, Pará State, North of Brazil and the perspective of elimination

Com o objetivo de caracterizar a situação epidemiológica da filariose linfática em Belém-PA foram analisados dados dos inquéritos hemoscópicos de 1951 a 2003. As informações do período de 1951 a 1994 foram coletadas de relatórios disponibilizados pela Fundação Nacional de Saúde. Os dados de 1995 a 2003 foram obtidos através de inquéritos realizados em 62 bairros, dos oito distritos administrativos da cidade. Observou-se uma queda apreciável ao longo dos anos nos índices de microfilarêmicos. As percentagens de parasitados nas décadas de 1950, 1960, 1970, 1980 e 1990, foram respectivamente: 8,2 por cento, 2,6 por cento, 0,7 por cento, 0,16 por cento e 0,02 por cento. Em 2001, foi diagnosticado um único microfilarêmico, interrompendo uma série de dois anos sem registro de exames positivos na cidade. Em 2002 e 2003, inquéritos hemoscópicos e entomológicos foram realizados, simultaneamente, não sendo detectados indivíduos microfilarêmicos ou mosquitos infectados. Para manter essa tendência, medidas de vigilância devem ser observadas, a fim de detectar e tratar precocemente pacientes, para evitar o risco de ressurgimento dos focos, aparentemente já controlados.

Knowledge on lymphatic filariasis and the response to July 2002 mass treatment campaign in two communities in the Galle district.

OBJECTIVE: To ascertain the knowledge on filariasis and response to the July 2002 mass treatment campaign in two sample populations. DESIGN: Application of pre-tested questionnaire by direct interviews of individuals from randomly selected streets. METHODS: Study areas were a coastal community in Unawatuna (population sample 381), and an inland community in Baddegama (population sample 236) in the Galle district. They were interviewed twice, 4 weeks before the mass drug administration (MDA) and 4 to 7 days after. RESULTS: The sample population of Unawatuna had a greater awareness of the clinical and parasitological features of the disease (p = 0.0003) and the drug treatment (p = 0.00380 than that of Baddegama. Only 5.5% of the combined sample attributed the cause of filariasis to a parasitic worm. However, over 70.0% of them knew that transmission was through mosquito bites. Volunteers formed 87.5% of the work force used for drug distribution in Unawatuna and 70.1% in Baddegama. The balance work force were Grama Niladaris and Public Health Midwives. Drugs were received by 76.9% of the Unawatuna sample compared with 89.0% at Baddegama (p < 0.001). Among those who received the drugs, consumption was 91.8% in Unawatuna and 96.2% in Baddegama. Taking the two communities together adverse effects were experienced by 22.9%. These effects in night time drug consumers (10.4%) were significantly less than in day time consumers (19.8%) (p < 0.005). The adverse effects were sleepiness (37.8%), malaise (28.2%), headache (16.8%), vomiting (5.1%), nausea (4.5%) and fever (3.9%). The message of mass treatment was carried to the community by the people themselves on the eve and on the day of drug distribution. Over 95% agreed that in future programs drugs should be delivered to their homes.

Compliance with the mass chemotherapy program for lymphatic filariasis.

OBJECTIVE: To evaluate compliance with the single dose mass chemotherapy program for control of filariasis, and to determine factors influencing compliance in the Gampaha district. DESIGN: A prospective study employing a pre-tested self-administered questionnaire. METHODS: Four groups comprising individuals over one year old with residence in the Gampaha district for over one year were surveyed. Data collection was started two weeks after the mass chemotherapy program. RESULTS: 2300 questionnaires were distributed, 1983 (86.2%) were returned, and 1935 (84.1%) were sufficiently complete for analysis (857 males; mean age 39 years, SD = 19.5). Over 96% had heard of filariasis and the mass chemotherapy program, but only 60.3% of those over 11 years of age were aware of asymptomatic carriage of the parasite. 1289 (66.6%) out of the total sample surveyed (1935 individuals) had obtained the diethylcarbamazine tablets, and 1221 (63.1%) had taken the drug. Of the possible demographic factors that could have influenced compliance only educational level seemed to play an independent significant role, compliance being lowest at both extremes of educational level. The main problem with compliance was obtaining the drug from distribution centres. CONCLUSIONS: Compliance with the mass chemotherapy program to control filariasis needs improvement. Strategies should include a better system for distributing the drug, and altering the content of the publicity material used by the program to target less compliant groups, and improve aspects of knowledge regarding filariasis that seem inadequate at present.

A statistical approach to monitor ongoing intervention for control of lymphatic filariasis.

Lymphatic filariasis is a major public health problem, affecting 120 million people in 73 countries. One-third of the infected people infected with lymphatic filariasis live in India. Newer tools and control strategies have encouraged the hope of its elimination. One of the components in the elimination strategy is treating the entire population with a single dose of DEC annually to reduce microfilaraemia load. In India, the programme of drug distribution on a community-wide basis was taken up in 1997 on pliot scale in 13 districts within the existing public health system network. In developing epidemiologic approach to monitor and evaluate the success of ongoing intervention the utility of Lot Quality Assurance Sampling techniques for corrective measures by the programme managers is presented and discussed in this paper.

Long-term effect of diethylcarbamazine citrate on microfilaraemia status in treated individuals.

Follow up of microfilaraemic individuals infected with Wuchereria bancrofti at five years after treatment was carried out in a tea workers population. Diethylcarbamazine citrate in the dose schedule of 72 mg/kg body weight given in equal daily doses over a period of 21 days cleared 51.6 per cent microfilaraemic individuals five year post-treatment. Eighty five subjects were successfully followed and among these, 10 (11.8%) showed increase in mf counts, 31 (36.4%) showed reduction but remained microfilaraemic and 44 (51.8%) became amicrofilaraemic. The age and sex of the host had no significant effect on the clearance of mf. Persistence of a relatively stable low number of mf in treated individuals is more likely due to survival of one or more female worms after the therapy or due to reinfection which could not be ruled out in the present study. Overall, findings indicated that diethylcarbamazine citrate appeared to give a long-term benefit to treated individuals.

Early development of acute filariasis in a migrant from non-endemic to hyper endemic area: a case report.

A case report of a European woman who contracted filariasis after staying for a few weeks in a filaria endemic area of south India is presented in this paper.

Efficacy of diethylcarbamazine-medicated salt for microfilaraemia of Brugia malayi.

BACKGROUND: Pilot studies in India and abroad have demonstrated the benefit of cooking salt fortified with diethylcarbamazine citrate (DEC) for the control of lymphatic filariasis. In India, DEC-medicated salt has been introduced on a commercial basis in the Cherthala region of Kerala, which is endemic for Brugia malayi (B. malayi). We studied the efficacy of DEC-medicated salt in the clearance of microfilaraemia of B. malayi. METHODS: Eighteen cases of microfilaraemia (11 men; 7 women) were selected; 14 in the experimental group (i.e. treated with 0.2% w/w DEC-medicated salt) and the rest as the control group who were given a placebo. The consumption of salt and the status of parasitaemia were monitored till all the microfilaria carriers became negative. RESULTS: There was a significant reduction in the density of microfilariae (intensity) among the treated individuals over a period of time. The duration required for the clearance of microfilariae ranged from 9 to 30 [mean (SD) 19.4 (1.7)] weeks. All microfilaraemics except one reported side-effects which were mild-to-moderate and persisted for a maximum period of one month. CONCLUSION: DEC-medicated salt effectively clears microfilariae within 30 weeks in parasitaemic individuals. No 'endemic normals' reported any side-effects, though these were common among the microfilaria carriers.

Dietilcarbamazina no tratamento da filariose bancroftiana / Diethylcarbamazine in the treatment of Bancroft's filariasis

Os autores realizaram uma ampla revisão sobre o tratamento da filariose bancroftiana com a droga dietilcarbamazina. Os aspectos interessantes sobre o histórico de sua descoberta e os conceitos básicos de sua farmacologia foram relatados de forma resumida. Ênfase especial, por outro lado, foi dada às especulações feitas pelos diversos autores sobre os achados intrigantes descritos na literatura. Foram trazidos os novos avanços sobre o conhecimento da doença, como por exemplo, a visualização pela ultra-sonografia do verme vivo de Wuchereria bancrofti, no seu hospedeiro natural, o homem. Isso possibilitou a compreensão de muitos dos achados aparentemente paradoxais encontrados na literatura sobre o tratamento da infeção com a DEC. Assim, devido à inexistência de uma droga sucessora que reunisse efeitos micro e macrofilaricidas ideais e aos novos conhecimentos sobre a bancroftose e sobre a própria dietilcarbamazina, foi-lhe conferido um novo realce. Esses aspectos a colocaram numa posição de destaque no cenário da infecção, à época do seu quase cinqüentenário de existência.

The authors presented a detailed review about the treatment of bancroftian filariasis with diethylcarbamazine. The interesting aspects about the drug discovery and the basic concepts about its pharmacology were reported in a summarised form. On the other hand, emphasis was made about the speculation done by several authors about the intriguing findings regarding its efficacy reported in the literature. Latter, it was brought the new advances about the disease, as for example, the visualization by ultrasound of living Wuchereria bancrofti adult worm on its natural host--the human being. This made possible the comprehension of several paradoxical issues reported, focusing the treatment of infection using diethylcarbamazine. So far, because of the lack of ideal drug with micro and macrofilaricidal properties, together with the new understand about the disease and the new parameters for monitoring the efficacy of the drug, diethylcarbamazine has back its importance conquered at the begin of its discovery, almost fifth years ago.

A preliminary study of filariasis related acute adenolymphangitis with special reference to precipitating factors and treatment modalities.

Episodic adenolymphangitis (ADL) is one of the important clinical manifestations of lymphatic filariasis. Recurrent ADLs contribute to the progress of the disease and also have important socioeconomic implications since they cause significant loss of man days. The present study was conducted in order to identify the precipitating factors responsible for ADL attacks and also to examine the different modalities of treatment. Sixty-five individuals with filariasis related ADL attacks, who are residents of Alleppey district (endemic for Brugia malayi) were studied. All efforts were taken to identify the precipitating factors for ADLs in these individuals. They were hospitalized for a period of five days or more. All of them received symptomatic antipyretic/antiinflammatory therapy and topical antibiotic/antifungal treatment of the affected limbs. They were then randomly allocated to one of the following four regimens: group I - symptomatic alone; group II - symptomatic plus antibiotics; group III - symptomatic followed by diethylcarbamazine citrate (DEC) and group IV - symptomatic plus antibiotic followed by DEC. Patients in groups III and IV received DEC every three months up to one year. There was a significant relationship between the number of ADL attacks and the grade of edema. Presence of focus of infection in the affected limb could be identified in 28 of the 65 patients. In the majority of patients (48) response to treatment was rapid (resolution in less than five days). Neither antibiotics nor DEC (given at intervals of three months) appeared to alter the frequency of ADL attacks. On the otherhand simple hygienic measures combined with good foot care and local antibiotic/antifungal cream application (where required), were effective in reducing the number of ADL attacks.

Double blind clinical trial on centperazine & DEC in bancroftian filariasis.

Centperazine, an analogue of DEC, was subjected to a double blind controlled trial, to evaluate its efficacy as a newer antifilarial agent. Centperazine (300 mg/day) along with equivalent quantities of DEC and placebo were administered to different types of filariasis patients. DEC was found to be significantly effective in reducing peripheral microfilaraemia, in different weeks and months of follow-up, except at the end of 6th month, as compared to Centperazine. There was no significant difference between the placebo and Centperazine treated patients, in this respect, revealing that the drugs had no efficacy in eliminating peripheral microfilaraemia. Recurrence of acute attack within 6 months was nearly equal with both Centperazine and DEC, being 28.2 and 24 per cent respectively, whereas in the placebo group the recurrence rate was 48.9 per cent. Centperazine treated patients showed significantly less side effects (8.9%), as compared to DEC treated patients (34%). Giddiness, nausea and vomiting were the common adverse effects observed.