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Loa loa presenting in a ThinPrep Pap test: case report and review of parasites in cervicovaginal cytology specimens.
Parasites other than Trichomonas vaginalis may occasionally present in Pap tests obtained during gynecologic examination. We present a case of Loa loa found on a Pap test from an apparently healthy 19-yr-old woman who had immigrated to the US at the age of 15 from Cameroon. We discuss the cytologic features from this case and then briefly review Loa loa and the presence of parasites in Pap tests and other cervicovaginal specimens.
Loa loa: immunological responses during experimental infections in mandrills (Mandrillus sphinx).
Six intact, adult mandrills (Mandrillus sphinx) were infected with human-derived, diurnal Loa loa infective larvae. Microfilaremia, hematological, and immunological parameters were followed for 2-4 years. A major aim was to investigate the relationship between specific humoral immunity to microfilariae and microfilaremia and also to assess whether infection led to generalized immune dysfunction. Microfilaremia was similar to previous studies for 4 mandrills, with a prepatent period of 153.5 +/- 10.1 days, a peak of 34-1,798 mf/ml around Day 200, followed by a decline to low, persistent microfilaremia. One mandrill (No. 20) had a longer prepatent period and very low, but persistent, levels of microfilaremia, and one (No. 19) had gradually increasing levels which remained > 10,000 mf/ml for 3 years. To assess generalized immune perturbations several parameters were studied. There was neither generalized leukocytosis nor relative or absolute eosinophila. Serum Ig concentrations were measured from 0-600 days postinfection by radial immunodiffusion using a rabbit anti-mandrill Ig serum, and these were remarkably stable. Proliferative responses of peripheral blood mononuclear cells from these infected mandrills and noninfected controls showed no significant differences in the magnitude of proliferation after stimulation with a range of doses of PHA, PWM, or Concanavalin A. Thus, no evidence of generalized immune dysfunction was found in the peripheral blood. Serum IgG levels to soluble mf antigens were estimated by an indirect ELISA and all animals had maximal levels around Week 22 postinfection, at the time of maximum microfilaremia, and these decreased over the next 2-3 years in all mandrills except No. 19, in which levels remained fairly constant. Serum IgG levels to adult worm antigens showed a similar pattern but were not, or were only slightly, diminished late in infection. Antibody to mf sheath antigens were detected by indirect immunofluorescence and agglutination of live mf. Antibody to sheath antigens were never detected in mandrill 19 but were present from Week 8 postinfection to 2-4 weeks before patency in all the others. Anti-sheath antibodies were not detected in serum at later time points, i.e., postpatency, in any mandrill, even at time points when microfilaremia was < 1 mf/ml. The anti-sheath antibody was IgM and no anti-sheath IgG was detected. Ig was detected on the surface of circulating mf in 1 mandrill (No. 20). The appearance of these antibodies prior to maturation of the adults indicates that certain L4 or immature adult antigens cross-react with the surface of mf.(ABSTRACT TRUNCATED AT 400 WORDS)
Loa loa: structural diversity of a 15-kDa repetitive antigen.
A ladder antigen of Loa loa was identified on Western blots of all life cycle stages probed with loaisis sera. The smallest subunit has a relative M(r) of about 15 kDa and larger subunits represent size increments of 15.0 kDa. An 1800-bp genomic clone encoding this antigen was characterized further by restriction mapping. Southern blot analysis, and nucleotide sequencing. The antigen is encoded by multiple copies of a gene, linked in tandem repeats of 396 bp, each of which encodes 132 amino acids. These repeats have diverged sufficiently to produce distinct restriction enzyme sites and Southern blot hybridization patterns. The 1764-bp insert contains no introns and encodes 588 amino acids, representing one incomplete and four complete repeats. At the 3' end of three repeats, there are consensus proteolytic cleavage sites; one repeat has no cleavage site. Two perfect repeats show a 93.9% amino acid identity with one another; the rest of the repeats, despite being adjacent to one another, show only 31-42% identical amino acids. Putative asparagine N-linked glycosylation sites are expressed by only two of the repeats. Despite this structural diversity, each L. loa repeat showed homology to Ascaris suum allergen and the homologue protein described in Dirofilaria immitis and Brugia pahangi.
Electron microscope study of the body wall and the gut of adult Loa loa.
The morphology of the body wall and the gut in the midbody region of adult male and female Loa loa originating from patients in Gabon was studied by transmission and scanning electron microscopy. The cuticle of the dorsal and ventral regions consists of ten layers. In the lateral regions the cuticle is thicker and includes two additional layers. The thin hypodermis contains numerous transhypodermal fibres. A row of median cells is situated between the syncytia in each lateral chord. No intracellular bacteria were observed. The cross-sections of each of the four muscle sectors are comprised of approximately 12 muscle cells of the coelomyarian type. The plasm of the gut cells contains large vacuoles and several mitochondria. The intestinal wall surrounds a wide lumen filled with material which occasionally contains cellular structures. The morphology of L. loa is compared with that of adult Onchocerca volvulus and Brugia malayi. The gut of the adult L. loa has the typical nematode morphology, which might be an indication of its normal function in nutrition. The multilayered cuticle with the rather smooth surface, and the prominent muscles correspond to the migratory activity of this filaria.
[Immunological diagnosis of filariosis in persons returning from tropical countries and in European and indigenous inhabitants of endemic areas (author's transl)].
Serum samples from persons who lived in areas where onchocerciasis occurred or who had filariasis were examined with the complement fixation test and the indirect hemagglutination test for the presence of antibodies against crude extracts from Dirofilaria immitis, Onchocerca volvulus, Dipetalonema viteae, and Ascaris suum. The results could be interpreted as follows: 1. The indirect hemagglutination test was more sensitive than the complement fixation test for the demonstration of antibodies in sera from European and indigenous inhabitants of endemic areas. 2. There were no differences between the responses to the four crude worm extracts among the groups of 21 patients with Loa loa, 12 patients with Onchocerca volvulus, 11 patients with Dipetalonema perstans, and 22 patients with clinical filariasis in whom no microfilaria had been found. It was concluded that the examination with crude extracts cannot give any information about the antigens that had caused the stimulation of antibodies.
[Asthenoscopic problems with a subconjunctival worm].
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[Ocular involvement in systemic Loa-Loa filariasis. Case report and review of the literature].
BACKGROUND: Within the last few years there is more and more evidence for nonspecific ocular symptoms caused by "exotic" pathogens. We herewith report another case of such an infection to underline the increasing importance and diagnostic relevance even of rare diseases. PATIENT: A 35-year-old female German patient presented with recurrent left retrobulbar "feeling of pressure" after a 6-month-stay in Central Africa 5 years ago. In addition, she reported on repeated swelling of the skin and joints of her hands and arms. Multiple ophthalmologic and rheumatologic investigations had been carried out without diagnostic results. Her ophthalmologist referred her with the presumed diagnosis of a subconjunctival worm. RESULTS: Slit-lamp biomicroscopy confirmed the original suspicion, and after topical anesthesia a female Loa-Loa worm was easily removed with forceps through a conjunctival incision. The general examination showed symptoms of systemic infection (calabar swelling, eosinophilia). Classification and initiation of treatment with diethylcarbamazine and mebendazole were carried out by the University Institute of Parasitology. CONCLUSION: Loa-Loa is a parasitic infection endemic in the tropical rain forests of Western, Central, and Eastern Africa. It is transmitted by the Chrysops fly. An increasing number of oculosystemic infections in non-African patients with Loa-Loa are being published. Therefore, any patient with an unclassifiable eye affection should also be investigated for those rare pathogens.
[Stabbing pain, conjunctival changes, foreign body sensation and unilateral red eye. Subconjunctival macrofilariasis in systemic Loa loa filariasis].
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Current considerations on a Loa loa simian reservoir in the Congo.
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Hypogonadism and ecdysteroid production in Loa loa and Mansonella perstans filariasis.
Possible endocrinological repercussions of infection with Loa loa and Mansonella perstans filariae were studied in Gabonese subjects. Microfilaremic males were compared with amicrofilaremic controls. In the infected group 13/105 subjects (12%) presented only abnormally low serum levels of testosterone (less than 4 ng/ml), 25/105 (24%) only abnormally high serum levels of gonadotrophins, FSH (greater than 15 mIU/ml) and LH (greater than 20 mIU/ml), and 22/105 (21%) presented anomalies in both testosterone and gonadotrophin levels. One out of 68 control subjects had 3.6 ng/ml seric testosterone and all had normal levels of gonadotrophins. Ecdysteroids were detected (greater than 0.025 ng/ml) in the serum of 87/97 (90%) microfilaremic subjects (GM 0.123 ng/ml) compared to 12/64 (19%) controls (GM 0.030 ng/ml). Ecdysteroids were detected in the urine of all subjects, infected (GM 8.468 ng/ml) as well as control (GM 1.245 ng/ml). The hormonal perturbations were correlated with the levels of Loa loa microfilaremia but not with those of serum and urinary ecdysteroids. These results demonstrate that microfilaremic subjects often show endocrinal signs of hypogonadism and present appreciable levels of ecdysteroids in serum and urine. A direct role for parasitic ecdysteroids in hypogonadism remains to be demonstrated.
Steroid and gonadotropin hormone levels in young African women with filarial infection.
Serum levels of dehydroepiandrosterone sulfate (DHEAS), testosterone (T), progesterone (P), estradiol (E2), prolactin (PRL), cortisol (F) and gonadotropins (FSH, LH) were analysed by radioimmunoassay for 125 schoolgirls aged 14-16, in a zone of endemic filariasis 3 days after menses. Two groups were identified: the infected group in which 38 subjects had circulating Loa loa and or Mansonella perstans microfilariae as determined by the Knott's concentration technique, and the non-infected group (87 subjects without microfilaremia). All results are expressed as the mean +/- SD. No significant difference was found between the two groups for age (14.47 +/- 1.37 yr vs 14.50 +/- 1.37 yr) or for body wt (46.10 +/- 8.45 kg vs 47.06 +/- 8.26 kg). There was a tendency to lower levels of DHEAS in the infected group by comparison with controls (54.92 +/- 37.34 micrograms/dl vs 66.80 +/- 47.18 micrograms/dl) while in the same infected group more subjects had higher levels of prolactin by comparison with the control group (10.85 +/- 14.16 ng/ml vs 9.80 +/- 5.56 ng/ml). Testosterone, progesterone, estradiol levels and the LH/FSH ratio were lower in the infected group than in the non-infected group (P: 0.25 +/- 0.12 ng/ml vs 0.33 +/- 0.20 ng/ml, P less than 0.025; T: 0.55 +/- 0.17 ng/ml vs 0.62 +/- 0.19 ng/ml, P less than 0.05; E2: 32.95 +/- 19.63 pg/ml vs 66.98 +/- 54.83 pg/ml, P less than 0.001; LH/FSH: 0.91 +/- 0.44 vs 1.30 +/- 0.84, P less than 0.005) respectively. No significant difference was found between the two groups for F; however FSH levels correlated negatively with F levels only in the microfilaremia group (r = -0.38, n = 38, P less than 0.05). Our results suggest that the presence of microfilaremia in our subjects may have contributed to reduced steroid levels, perhaps by involvement of the cyclic AMP kinase system. These observations may explain the delayed menarche and androgen secretion found during puberty in a similar population living in the same zone of endemic filariasis. Microfilaremia should therefore be considered an environmental factor which mediates endocrine disorders in subjects living in tropical filariasis areas.
Loa loa infection without microfilaraemia.
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Investigations on the level of circulating eosinophils throughout a 24 hour period in parasitic disease.
Circulating absolute eosinophil levels were studied over a 24 hour period in a series of 10 patients with presumed parasitological disease. Seven of these ten had the distinct nocturnal increase and a percentage swing paralleling that found in normal subjects. Three patients had a reversed pattern. The latter were thought to have one or other form of filariasis. Two patients with loasis and a "physiological response" had suppression as anticipated to exogenous steroid. It is concluded that steroid administration will not separate parasitic from other causes of eosinophilia.
Survival of Loa loa following transplantation from drills (Mandrillus leucophaeus) into jirds (Meriones unguiculatus): parasitology and pathology.
Two drills infected with Loa loa maintained a microfilaraemia for four and a half years ranging from less than 1 mf/100 microliters to 1150 mf/100 microliters. No significant tissue reactions to the adult worms were seen at autopsy. Adult worms were transplanted into the peritoneal cavities of naive jirds when a persistent microfilaraemia first developed by 17 days. Retransplantation of adult worms into naive jirds produced a microfilaraemia and microfilariae in the peritoneal cavities of three out of five animals. These three animals were all negative for circulating parasites by eight and a half months. The tissue reactions to the worms in the jirds are described, including a granulomatous response surrounding adults and a myositis involving microfilariae.
Loa loa: a simple method for isolation of microfilariae from blood with production of antigen in extraction medium.
A simple method for isolating Loa loa microfilariae from the blood of patients is described. This involves sedimentation on Ficoll followed by migration of the microfilariae into an extraction medium. During migration the microfilariae release antigen-rich excretory or secretory products. The procedure thus yields two products: pure microfilariae and large amounts of antigen in the extraction medium.
Malaria and loaisis among blood donors at Ibadan, Nigeria.
115 blood donors were screened for the presence of malaria and other blood parasites at the Blood Bank, University College Hospital, Ibadan, between January and July, 1984. 11.3% of these had blood parasites; 7.8% had Plasmodium falciparum with parasitaemias from 0.03-0.2%, and 3.5% had Loa loa microfilaraemia. No other blood parasites were observed. Serological examination by the indirect fluorescent antibody test revealed that 86% of the donors had malaria antibody with reciprocal titres ranging from 16 to 512. There was no significant association between ABO blood group and malaria parasitaemia or antibody titre.