Subconjunctival localization of a Wuchereria bancrofti adult female]

The authors describe a case of conjunctival localization of a living adult Wuchereria bancrofti female observed in a 6 year old native Haitian girl, two years after her arrival in France. The adult was surgically removed from the conjunctiva. Microfilariae were evidenced in blood samples obtained at midnight. This is the first case of sub-conjunctival localization of W. bancrofti. This case stresses the necessity to identify the filaria by studying the microfilariae in blood samples obtained at different times of the nycthemere and/or by observing the adult after surgical extraction. The presence of a Loa, a Dirofilaria, a Mansonella, or a Wuchereria calls for different medical therapies.     

Cloning and characterization of a potentially protective chitinase-like recombinant antigen from Wuchereria bancrofti.

While there is no direct evidence demonstrating the existence of protective immunity to Wuchereria bancrofti infection in humans, the presence of individuals, in populations in areas where infection is endemic, with no clinical evidence of past or current infection despite appreciable exposure to the infective larvae, suggests that protective immunity to filarial parasites may occur naturally. Earlier work indicated that such putatively immune individuals generated antibodies to a 43-kDa antigen from larval extracts of the related filarial parasite Brugia malayi that was recognized by only 8% of the infected population. With rabbit antiserum raised against this 43-kDa antigen, this current study identified a recombinant clone, WbN43, with an insert size of 2.3 kb, from a W. bancrofti genomic expression library. The recombinant fusion protein was differentially recognized by the putatively immune individuals but not by the infected patients. The coding sequence (684 bp) from the 5' end had significant sequence similarity to chitinases from Serratia marcescens, Bacillus circulans, Streptomyces plicatus, and B. malayi. Peptide sequencing of the expressed product also defined a chitinase-like sequence. Molecular characterization indicated WbN43 to be a low-copy-number gene, with expression predominantly in infective larvae and microfilariae but not in adult parasites.     

Immunocytochemical localization of surface antigens in microfilariae of Wuchereria bancrofti

Antigenic sites were localized on the surface structure (sheath and cuticle) of microfilariae of Wuchereria bancrofti using sera from microfilaraemic and amicrofilaraemic patients using antibodies associated to colloidal gold particles and transmission electron microscopy. No labeling was observed on the surface of intact parasites. Microfilariae without the sheath and isolated sheath were obtained by ultrasound treatment. Using these preparations labeling of the inner portion of the sheath was observed when sera from amicrofilaraemic patients were used. Labeling of the cuticle surface was observed mainly in the regions of the cuticular annulations.     

Microfilariae of Wuchereria bancrofti in urine: an uncommon finding

Filariasis is a global health problem commonly seen in tropics and subtropics. Microfilariae has been reported in cytological specimens from various sites but is an unusual finding from sediments of centrifuged normally voided urine samples. This highlights the presence of adult worms in the lymphatics and thus helping in prompt decision to start antihelminthic treatment besides providing surgical treatment for chyluria.     

Detection of amplified Wuchereria bancrofti DNA in mosquitoes with a nonradioactive probe.

A technique to identify Wuchereria bancrofti larvae in mosquito vectors with an enzyme-labeled DNA probe is described. To overcome the low sensitivity of nonradioactive detection methods, analyte DNA was amplified by polymerase chain reaction (PCR). Oligonucleotide primers were used to amplify W. bancrofti-specific DNA fragments of 380 and 650 bp, respectively. Parasite DNA in mosquito extracts was isolated free of inhibitors of the PCR by hybridization to a biotinylated DNA fragment (IWb 67), which hybridizes to DNA from most filarial species, followed by absorption of the resulting DNA hybrids onto avidin-coated acrylic beads. PCR-amplified DNA was detected with a biotin-labeled W. bancrofti-specific repeat DNA (IWb 35) coupled to avidin-alkaline phosphatase and the chemiluminescent substrate, AMPPD. The DNA equivalent of less than one larva can be detected by this method in mosquito extracts. The sensitivity of detection was comparable to that of radioactive probes and the assay is suitable for field application in endemic countries.     

Antibodies to diethylcarbamazine cross-react with microfilariae of Wuchereria bancrofti

Antibodies directed against the microfilarial sheath have been instrumental in the immune elimination of circulating microfilariae in human lymphatic filariasis. We report here that antibodies to diethylcarbamazine (DEC, the most commonly used anti-filarial drug) cross-react with the sheath of Wuchereria bancrofti microfilariae. Antibodies with reactivity to DEC were raised in rabbits by immunization with a conjugate of methylpiperazine carboxylic acid (MPCA, an acid hydrolysis product of DEC) coupled to bovine serum albumin. The reactivity of these antibodies with microfilarial sheath of W. bancrofti was demonstrated by indirect immunofluorescent assay and indirect immunoperoxidase assay. This reactivity could be effectively inhibited by pre-incubation of the antisera with different haptens such as DEC, MPCA or piperazine citrate.     

Prognostic factors from the fine-needle aspirate: Breast carcinoma nuclear grade

Two of the most important microscopically derived morphologic prognostic factors for breast carcinoma patients are histologic type of tumor and nuclear grade. The recent literature stresses the importance of including these parameters in the surgical pathology report, yet there is little information in the cytology literature regarding the reporting of the nuclear grade of breast carcinomas from fine-needle aspirate biopsies (FNAB). In this retrospective study, we examined 104 ductal carcinomas of the breast in order to determine whether the FNAB derived nuclear grade and morphologic aspects of histological grading such as tubule formation and mitoses could accurately correlate with the same parameters on the tissue specimens. There was a correlation of 87% between the nuclear grade assigned by FNAB and the nuclear grade assigned to the tissue sample. Both the Diff-Quik and the Papanicolaou staining methods were assessed in this study and both gave comparable nuclear grade results. Tubule formation was difficult to assess on the cytologic samples and mitoses showed no correlation between cytologic and tissue specimens. The FNAB sample was not representative of the tissue nuclear grade in only 4.8% of the cases. Nuclear grade is especially important in patients treated with chemotherapy prior to definitive therapy for breast carcinoma. We conclude that the nuclear grading of breast carcinomas is performed with ease, correlates well with tissue nuclear grade, and, as a fundamental cytologic parameter, should be included in the fine-needle aspirate biopsy report whenever possible. © 1994 Wiley-Liss, Inc.     

Case report and brief commentary: Wuchereria bancrofti and Onchocerca volvulus co-infection in a refugee from Sierra Leone

Filarial infection is endemic in the tropics and is a public health problem in Africa, Asia, South and Central America, and the Pacific Islands. Co-infection with filarial nematodes, if unrecognized, can result in untoward therapeutic consequences. We report a case of co-infection of Wuchereria bancrofti and Onchocerca volvulus that was diagnosed by direct blood smear (W. bancrofti ) and serology (O. volvulus) in a native of Sierra Leone. We comment briefly on the therapeutic implications of the co-infection.     

Immunocytochemical localization and distribution of human albumin in Wuchereria bancrofti adult worms

To determine whether albumin is present on adult worms of Wuchereria bancrofti, thin sections of resin-embedded parasites were incubated with a specific antiserum to human albumin. With the exception of the epicuticle, all layers of the cuticle and the hypodermis were intensely labeled. Concentration of gold particles was observed within infoldings of the hypodermal membrane. Moderate labeling of the thin basement membrane that lines the pseudocelomic cavity and the gonoduct was also observed. Within the uterus, ovular membranes labeled intensely; groups of organized particles were seen below ovular membranes and also within invaginations of microfilarial embryos. In contrast, few gold particles were seen on the surface of mature intrauterine microfilariae. No labeling was observed in control sections incubated with antiserum preadsorbed with purified human albumin. The findings suggest that human albumin may be essential for the nutrition and development of W bancrofti microfilariae.