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Histochemical enzyme pattern of microfilaria of Setaria cervi.

The present study deals with the histochemical localization of glucose-6-phosphatase, malic dehydrogenase and aldolase in the microfilaria of Setaria cervi. Marked activity of glucose-6-phosphatase was observed in the cephalic cells, excretory and anal pores, G-cells and Innenkörper. Malic dehydrogenase activity was noted throughout the body (including cuticle) of the microfilaria except for Innenkörper. Intense aldolase activity was observed in the excretory pore and G-cells only. Muscle cells and anal pore were negative for this enzyme.

Animals↗

Selective recovery of living microfilariae from Onchocerca volvulus nodules. Determination of optimal conditions for their culture in vitro for excretory/secretory products.

A method for the selective recovery of living microfilariae from Onchocerca volvulus nodules is described. The microfilariae migrate through solidified agar gel into overlayering Hanks balanced salt solution (HBSS). The highest recovery rates of the worms were obtained with 0.3 and 0.4% agar. Optimal conditions for in vitro cultures of the larvae in HBSS were established; pH range 7.0-7.5, glucose concentration 2-5 mg/ml for long term cultures, osmolality 200-309 mOsmoles/l, temperature 4 degrees C for prolonged cultures and 24-28 degrees C for overall best yield of excretory/secretory products (ESP). Subculturing of the larvae reduced contamination of ESP with human serum protein to minimal amounts after 9 recultures done within 96 h.

Animals↗

Diethylcarbamazine dependent, complement mediated, adherence and cytotoxicity of cells on microfilariae of Litomosoides carinii.

Diethylcarbamazine (DEC) induced dose dependent adherence of normal spleen cells from Mastomys natalensis to microfilariae of L. carinii in the presence of serum from Mastomys infected with L. carinii or normal serum. The effect could be also induced, using fresh, normal human serum and human blood leucocytes. The responsible serum factor was heat labile (56 degrees C, 30 min) and was eliminated from the sera by pretreatment with Inulin. The activity could be reconstituted by normal serum. Cell adhesion was inhibited by 0.004 MEDTA while 0.004 M EGTA had only a weak inhibitory effect. The addition of Mg++ led to high adherence rates in the presence of EGTA. The data indicate that DEC activates complement on the surface of the larval sheath by the alternate pathway. Adherent Mastomys cells or human cells had a cytotoxic effect on the larvae. The death of the microfilariae did not depend on the loss of the larval sheath.

Animals↗

A microfilaria of exceptional size from the ixodid tick, Ixodes dammini, from Shelter Island, New York.

Thirty or more microfilariae 0.70-1.32 mm in length were recovered from the hemocele of an unengorged adult tick, Ixodes dammini, that was collected from vegetation on Shelter Island, New York. Among approximately 500 I. dammini collected from the same area only 1 other was similarly infected. Outstanding features, in addition to size, were absence of a cephalic space and the presence of nuclei in 2 or 3 irregular rows extending to the end of a bluntly rounded tail. The microfilariae apparently were ingested in a blood meal that was taken when the ticks were larvae or nymphs, and had persisted alive without development.

Animals↗

Studies on the concentration of Onchocerca volvulus microfilariae in the skin in relation to the nodule.

The concentration of microfilariae in the skin over and at distance sup to 10 cm from the onchocercal nodule was studied in eight patients with established onchocerciasis. In spite of wide variations in microfilarial counts from snips taken from the same patient no significant differences were found in respect of distance or direction from the nodule. It is concluded that microfilariae are uniformly distributed in the skin around and onchocercal nodule in established infections.

Adult↗

Blood parasites of birds in Central Europe. 4. Trypanosoma, "Atoxoplasma", Microfilariae and other rare haematozoa.

The present paper, the last in the series on avian blood parasites in Central Europe, summarizes the data on parasites of the genera Trypanosoma, "Atoxoplasma", "Lankesterella", microfilariae and spirochaetes found in this region. Trypanosomes occur most frequently in Columbiformes, Corvidae, Galliformes and Strigiformes, while "Aloxoplasma" is encountered only in passerines, most frequently in Fringillidae, Passeridae and Hirundinidae; "Lankesterella" is to be found only in two species of passerines. Microfilariae occur in Corvidae and Galliformes, and spirochaetes were encountered in the blood smears from four birds only. All these organisms are very rarely found in birds due to the fact that the blood smears made from peripheral blood of birds are unsuitable for the diagnosis of these parasites.

Animals↗

Acute response of pulmonary blood flow and right ventricular function to Dirofilaria immitis adults and microfilaria.

Pulmonary arterial pressures, right ventricular pressures, and right ventricular force of contraction (max dP/dt) were measured before and after the surgical addition of Dirofilaria immitis adults and microfilaria. Six adult anesthetized and heparinized dogs were studied during thoracotomy to compare these pressure measurements with left caudal pulmonary arterial flow. Diversion of pulmonary flow was performed to obtain incremental increases in pulmonary flow through the left caudal lobar artery and to increase right ventricular afterload. The addition of adult heartworm disease, microfilaria, or both did not produce either pulmonary arterial hypertension or increase right ventricular pressure and force of contraction.

Animals↗

[Presence of microfilariae in the anterior chamber of the eye onchocerciasis].

Observation of a patient presenting 34 microfilariae in the anterior chamber of one eye, with negative biopsies, two small nodules and punctiform onchocercosis keratitis elementary microlesions. The patient has been observed five times during more than one hour each time. The author reviews the results of different surveys he has carried out in America and Africa, and which showed that the presence of microfilariae in the anterior chamber of the eye did not seem to forebode severe ocular lesions.

Africa, Western↗

Cholinesterase activity in the microfilaria of Wuchereria bancrofti Cobbold.

The distribution of cholinesterase activity in the microfilaria of the nocturnally periodic Wuchereria bancrofti has been described. Using histochemical methods, cholinesterase activity has been demonstrated in the amphids (Mundgebilde), phasmids (Schwanzgebilde), nerve-ring, excretory and anal vesicles of the microfilaria. It has been found that the enzyme activity disappeared completely after treatment with the specific cholinesterase inhibitor eserine. Evidence is presented that the greater amount of the cholinesterase activity detected is related to acetylcholinesterase and the functional significance of the enzyme in the enzyme reactive structures is discussed.

Acetylcholinesterase↗

[Histochemical changes in Brugia malayi microfilariae-infected Anopheles sinensis].

Histochemical changes in normal and Brugia malayi microfilariae-infected Anopheles sinensis were observed using histochemical technique. The results showed that the activity of alkaline phosphatase (AKP) and acid phosphatase (ACP) and the content of glycogen and basic protein in Brugia malayi microfilariae-infected Anopheles sinensis were less obviously than those of the normal control. Esterase (EST) activity was reduced slightly and acetylcholinesterase (AChE) remained no change in infected mosquitoes compared with the normal control. It is suggested that the development of filaria larvae in vector mosquitoes has selective effect on their biochemical metabolism.

Acid Phosphatase↗

A case of probable transplacental transmission of Wuchereria bancrofti microfilariae.

A case of transplacental transmission of Wuchereria bancrofti microfilariae is reported in endemic are of Bauchi State, Nigeria. The diagnosis was based on the history of illness, clinical symptoms, age of the child and presence of sheathed microfilariae of nocturnal periodic form of W. bancrofti in the peripheral blood films. Also the night blood sample collected from the child's mother revealed mf of W. bancrofti in addition to the unilateral elephantiasis of the hindlimb. The implication of this observation is stressed.

Adult↗

[Occurrence of microfilariae Dipetalonema rugosicauda (Bohm and Supperer, 1953) in deer and selected hunting grounds].

Examinations were carried out in Białowieska Forest, Borecka Forest, Lower Silesian Forest, woods in Olsztyn District, Słowiński National Park, and in experimental hunting areas of the Forest Research Institute in Iława and of the Warsaw Agricultural University in Rogów. Samples of the skin from the ear and nose were taken from 136 shot roe deers. Skin samples were cut into 1-2 mm pieces, incubated in a physiological solution in 25 degrees C for 24 hours and examined for the presence of microfilariae. Microfilariae of Dipetalonema rugosicauda were found in roe deers in all examined hunting grounds. Prevalence of invasion oscillated from 6.6% to 57.1%. The wide dispersion of D. rugosicauda in Poland is caused by common occurrence in our country of the intermediate host and vector of this nematode--tick Ixodes ricinus.

Animals↗

Spatial and temporal variations in prevalence, intensity and aggregation of microfilaria in the human host.

The prevalence, intensity and the frequency distribution of microfilaria (mf) of Wuchereria bancrofti in the human blood and their variation in time (pre-vector control, control and post control periods) and space have been examined. The prevalence and intensity showed significant variation between time and different areas of urban Pondicherry. The significant reduction in the prevalence and intensity of microfilaremia in the areas of high endemicity indicated that the effect of vector control was well marked in these areas. The distribution of microfilaria in human population was adequately described by the truncated negative binomial prior to interruption of transmission, and the dispersion parameter 'k' of the negative binomial varied between 0.17 and 0.68. A change in the distribution was observed after the 5 years of vector control, during which the transmission was completely interrupted. The increased 'k' values suggest that the distribution of mf is influenced by the degree of exposure to infection. Therefore, comparison of changes in the parameter 'k' can be considered as an additional tool for evaluating the control operations aimed at interrupting the transmission.

Animals↗

Microfilariae of Wuchereria bancrofti in a lymph node aspirate. A case report.

Microfilariae of Wuchereria bancrofti were detected by fine needle aspiration biopsy (FNAB) in an axillary lymph node from a 27-year-old female. The patient also had intestinal tuberculosis. A routine hemogram did not show any eosinophilia, and three consecutive night blood samples also were negative for microfilariae. This was an early case of filariasis without microfilaremia and was detected by FNAB of the lymph node. The association of filariasis and tuberculosis was purely coincidental.

Adult↗

Microfilariae in the cerebrospinal fluid, and neurological complications, during treatment of onchocerciasis with diethylcarbamazine.

Microfilariae of Onchocerca volvulus were found in the cerebrospinal fluid (CSF) of 5/8 heavily infected onchocerciasis patients. During treatment with diethylcarbamazine citrate 10/11 patients showed increased numbers of 0. volvulus microfilariae in the CSF. Patients with concentrations of 8-31 mf/ml CSF developed severe vertigo, and some other neurological manifestations, during treatment. A hypothesis is put forward to account for this clinical piciture, and its importance in relation to the treatment of onchocerciasis is discussed.

Arachnoid↗

IL-5-dependent immunity to microfilariae is independent of IL-4 in a mouse model of onchocerciasis.

Th2 lymphocyte responses under the control of IL-4 and IL-5 are frequently associated with protective responses to parasitic helminths. Studies on the role of these cytokines in acquired resistance to parasitic nematodes indicate that, in the case of gastrointestinal nematodes, immunity is mediated by IL-4, while immunity to tissue-dwelling nematodes is dependent on IL-5. Here we investigate the role of IL-5 and eosinophils in protective immunity to Onchocerca microfilariae in IL-4-deficient mice. In the absence of IL-4, and despite the up-regulation of Th1-type responses, immunity remains dependent on IL-5 and eosinophils. Protection was unaffected by the absence of Ab in B cell-deficient mice, confirming that IL-5 is not acting via either B cell differentiation, Ag presentation, or isotype switching mechanisms. These data demonstrate the dissociation of IL-4 and IL-5 in a functional model of protective immunity to a tissue dwelling nematode and cast doubt on the role of IL-4 in the generation of CD4+ T cell-mediated, IL-5-dependent immunity to Onchocerca microfilariae. Importantly, they also segregate T cell-mediated mechanisms of protective immunity from those characterized in ocular pathologic responses in onchocerciasis, which are dependent on IL-4.

Animals↗

Microfilariae identified in FNA of a thyroid nodule.

A patient presented with hyperthyroidism and a thyroid swelling, clinically thought to be malignant. Fine-needle aspiration of the thyroid nodule revealed microfilariae of Wuchereria bancrofti. After therapy the thyroid swelling subsided and the patient became euthyroid. The possible etiologic role of microfilariae in the genesis of the thyroid tumor and hyperthyroidism is discussed.

Animals↗

Onchocerca volvulus: a comparative study of in vitro neutrophil killing of microfilariae and humoral responses in infected and endemic normals.

In vitro neutrophil-mediated microfilarial killing, humoral responses to crude adult worm antigens (OVAg) and to four recombinant Onchocerca antigens (GST-OV7, GST-OV103, GST-OV3.6, and MBP-OV16), as well as Western blot analysis to stage-specific Onchocerca proteins were studied in individuals from Bassa County, Liberia, infected with onchocerciasis and in endemic normals, defined as individuals without microfilaridermia. Both groups exhibited high levels of specific serum-dependent killing of microfilariae but could not be differentiated on the basis of these results. However, infected individuals had a significantly higher frequency of antibody response to OVAg (P = 0.0001) except GST-OV103. Based on the pattern of response to the different antigens, 17 categories of specific recognition were observed. Nine of these categories were common to both the infected individuals and the endemic normals, 2 were unique to the infected individuals, and 6 were unique to the endemic normals. Among the endemic normals, we identified a subcategory of individuals who had nondetectable levels of total IgG to OVAg by ELISA and had significantly lower IgG4 responses to OVAg. These same individuals demonstrated evidence of past infection, based on serum antibodies detectable by Western blot analysis to male and female adult worms and skin microfilariae, and had a positive response to two or less of the recombinant antigens. We believe that this subcategory may represent individuals with a unique status of immunity.

Adolescent↗