Diagnosis Of Filariasis Research Articles

Evaluation of the filter paper blood collection method for detecting Og4C3 circulating antigen in bancroftian filariasis

Serological diagnosis of filariasis is generally known to be more reliable than detection of microfilariae. The recently developed Og4C3 enzyme-linked immunosorbent assay ( elisa) for detecting Wuchereria bancrofti circulating antigen has been shown to be very sensitive in diagnosing filiariasis using serum samples. The commercially available form of this elisa, using whole blood collected on filter paper, has not been validated independently. We evaluated the sensitivity of this new method against standard 20 μL night blood films in 1808 paired samples from 18 communities in different endemic areas of Ghana. The diagnostic performance of the method was consistently low in all but 2 communities (sensitivity = 50·3%). This method of diagnosing filariasis is not suitable for field use in its present form.

Evaluation of quantitative buffy coat analysis in the detection of canine Dirofilaria immitis infection: a model to determine its effectiveness in the diagnosis of human filariasis.

Quantitative buffy coat (QBC) analysis has been reported to have a high degree of methodical sensitivity in the detection of human filariasis. This study was conducted to evaluate its usefulness in the diagnosis of filariasis using a Dirofilaria immitis/dog model. By necropsy of 244 stray dogs, 40.6% of the animals were found to harbor 1-58 worms of D. immitis (mean 6.5 +/- 8.4 worms/infected dog). The QBC analysis and thick blood smear (TBS) method detected microfilaremia in 31.6% and 21.3% of these dogs, respectively. The results of these two methods were highly correlated with the presence of bisexual worms in the dogs. The QBC analysis was more sensitive (55% versus 39%) and efficient (79% versus 72%) than the conventional TBS method. However, accurate speciation of the microfilariae was impossible using the QBC analysis. Although this technique is more sensitive, simpler, and less time-consuming and does not require as much skill or experience in comparison with the conventional TBS method, the failure in speciation of the parasites may limit its usefulness.

Rapid Diagnosis of Brugia malayi and Wuchereria bancrofti Filariasis by an Acridine Orange/Microhematocrit Tube Technique

A microhematocrit tube technique for diagnosis of human filariasis has been previously described. A system incorporating heparin, EDTA, and acridine orange into a microhematocrit tube (Quantitative Blood Count, QBC) has been commercially developed for the quantitation of blood counts and has been used for the diagnosis of malaria. We evaluated this test for its usefulness in the diagnosis of filariasis. Upon centrifugation, the parasites were concentrated in the area of the buffy coat and could be observed through the wall of the tube. The parasites were concentrated further by a plastic float that expands the buffy coat and confines the parasites to the periphery of the tube. Acridine orange stains the DNA of the parasite, and morphologic characteristics can be examined by fluorescence microscopy. The terminal and subterminal nuclei and long cephalic space of Brugia malayi, as well as the short cephalic space and caudal nuclei of Wuchereria bancrofti, were easily recognized and differentiated from each other. Microfilariae were detected in samples diluted to a level of approximately 50/ml.

The slide agglutination test for the diagnosis of filariasis in camels.

The slide agglutination test was adapted for the diagnosis of filariasis in camels, using an antigen prepared from the microfilariae by a simple lytic technique. The preliminary results were satisfactory as the test detected 86 per cent of the infected animals. Only 6 per cent of the healthy camels with no blood parasites or microfilariae in their blood gave positive results and no positive reactions were obtained from 18 animals suffering from Trypanosoma infection.

Immunofluorescent reactions with microfilariae: 1. Diagnostic evaluation

Microfilariae have been evaluated as antigen for the indirect immunofluorescent test in the diagnosis of filariasis. Sonicated, unlike whole, microfilariae present no problems in handling on a slide. The cytoplasmic antigen that is exposed by sonication, unlike the sheath or cuticular antigen, reacts with filariasis sera irrespective of whether or not there is a detectable microfilaraemia. The cytoplasmic antigen of microfilariae of various species was marginally superior to Dirofilaria adult worm as antigen for diagnostic immunofluorescence in respect of both sensitivity and specificity. The microfilariae extruded from the uterus of an adult D. immitis were a useful source. But the best results were obtained with the sonicated microfilariae of Brugia pahangi, with which it was possible to utilize both cytoplasmic and sheath antigens simultaneously, giving a positivity rate of 95% for filariasis infections as a group. This test is thought to be the best available at present for the sero-diagnosis of filariasis, in spite of some lack of specificity. For individual filarial infections a homologous microfilarial antigen is probably the ideal.

The method of methacrylate--embedding of corpuscular antigen in the immunofluorescence diagnosis of filariasis (author's transl)

The method of methacrylate--embedding of corpuscular antigen in the immunofluorescence diagnosis of filariasis (author's transl)

Weber-Christian disease in the differential diagnosis of filariasis

Journal Article Weber-Christian disease in the differential diagnosis of filariasis Get access D.S. Ridley D.S. Ridley Search for other works by this author on: Oxford Academic PubMed Google Scholar Transactions of The Royal Society of Tropical Medicine and Hygiene, Volume 64, Issue 4, 1970, Pages 473–474, https://doi.org/10.1016/0035-9203(70)90051-9 Published: 01 January 1970

A Review of Immunologic Methods for the Diagnosis of Filariasis

The author reviews the historical application of the skin test, complement-fixation reaction, precipitin test, hemagglutination and bentonite flocculation, and Prausnitz-Kuestner test to the diagnosis of various filarial infections in man and animals, with a discussion of areas requiring further study. He is of the opinion that with standardization of techniques, immunologic methods can be made to furnish a reliable means of diagnosis, notwithstanding the past unreliablity of such methods. Five tables give brief summaries of pertinent papers in chronological order. A sixth table lists materials that have been used as antigens in the immunodiagnosis of filarial infections. A bibliography arranged in chronological order lists 125 papers covering the period from 1916 to 1962, and a supplementary list of references includes 22 recent papers on general aspects of the subject. Filariasis has been recognized as a clinical entity for hundreds of years. However, it was only during the latter part of the nineteenth century that the cause of the disease and the vectors of Wuchereria bancrofti and other filarial species were identified and their life cycles studied. In recent times filariasis research has been concerned with the epidemiology and pathology of the disease and, since the discovery of adequate chemotherapy, with the eradication of the infection in endemic areas. Diagnosis today is still dependent on the demonstration of microfilariae in blood or tissues of the infected individual, in spite of the fact that the parasitologic techniques are cumbersome, time consuming, and often inadequate. Serologic investigations were begun about 1916, and numerous excellent studies are reported in the literature. However, the use of immunodiagnostic techniques has fallen into disrepute. In 1961, Wilson (143) concluded that such tests were not satisfactory because most published accounts of other aids to diagnosis, such as skin reactions and complement-fixation tests indicate that they are not sufficiently specific and that 'false-negatives'

AN EVALUATION OF THE BENTONITE FLOCCULATION AND INDIRECT HEMAGGLUTINATION TESTS FOR THE DIAGNOSIS OF FILARIASIS.

Summary The indirect hemagglutination test and the bentonite flocculation test utilizing a saline extract of Dirofilaria immitis have been evaluated. The test was reactive with sera from individuals with infections of Acanthocheilonema perstans and showed higher titers for symptomatic patients with microfilariae in the blood. In a group of 42 symptomatic patients, 92% of 13 microfilariae-positive patients and 62% of 29 microfilariae-negative patients showed positive serologic tests. In a group of 15 asymptomatic individuals with microfilariae in the blood, 67% were positive. From a group of 295 asymptomatic-microfilariae-negative individuals, 21 sera (7%) were positive. Testing 632 sera from 295 normal missionaries, 84 normal Americans, and 253 individuals with various other parasitic and bacterial infections, an over-all non-specific response of 10% was obtained, utilizing the following criteria for a positive serologic test: (1) a hemagglutination titer of 1:200 or higher with a positive flocculation of 1:5 or higher, or (2) a hemagglutination titer of 1:400 with a negative flocculation reaction. Sera from 141 patients with helminth diseases showed a non-specific rate of 21%. This high rate was due to cross-reactions with trichinosis sera (35%) schistosomiasis (20%) and ascariasis (27%). Since the schistosomiasis and ascariasis sera were from individuals born in an area endemic for filariasis, the reactions may represent a serologic response to past experience with filariasis. Only 5% of 112 sera from individuals with non-helminthic diseases and 5% of 84 sera from normal individuals were positive.

The complement-fixation test in filariasis

The results of 517 filaria complement-fixation tests are analysed.It is concluded that D. immitis antigen gives a group reaction but that the incidence of positives is not equal for all types of filariasis, being greatest in loiasis, and lowest in cases of bancroftian infection. The test does not give false positive reactions, and is for this reason a useful aid to the diagnosis of filariasis during its early stages when microfilariae are absent.

Early Filariasis Diagnosis and Clinical Findings: A Report of 268 Cases in American Troops

Summary 1. 268 cases of early filariasis are presented. 2. The infection was contracted in three Pacific islands. No patients were seen that had not been in these areas. 3. 263 (98%) of the patients had been in the endemic areas four months or longer. 4. The observed incubation period varied from eight to sixteen months when the period of observation ended, with history of attacks as early as three months. 5. The mode of onset and clinical findings are described in detail. The tendency toward recurrences, the lack of severe constitutional reactions, the characteristic lymphangitis of extremity or genitalia and the adenopathy particularly in the epitrochlear region are stressed. 6. The intradermal reaction with Dirofilaria immitis antigen was positive in 90.8% of patients and 10.5% of a comparable number of control individuals. 7. Elevation of the total number of eosinophiles in the blood was present in 64.3% of the cases. 8. It is suggested that enlargement of the epitrochlear nodes and the intradermal reaction might be used as survey methods in approximating the incidence of filarial infestation in personnel residing in endemic areas.