Memórias do Instituto Oswaldo Cruz Fundação Oswaldo Cruz, Fiocruz ISSN: 1678-8060 EISSN: 1678-8060 Vol. 91, Num. 1, 1996, pp. 97-100

RESEARCH NOTE

Detection by Ultrasound of Living Adult Wuchereria bancrofti in the Female Breast

Gerusa Dreyer, Ana Carolina Brandao*, Fernando Amaral*, Zulma Medeiros, David Addiss**

Departamento de Parasitologia, Centro de Pesquisas Aggeu Magalhaes-FIOCRUZ, Av. Moraes Rego s/no, Cidade Universitária, 52020-200 Recife, PE, Brasil *Mediax, Memorial Imagem e Diagnostico, Recife, Brasil **Division of Parasitic Diseases, National Center for Infection Diseases, CDC, Atlanta, GA, USA

Code Number: OC96016
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Key words: ultrasound - Wuchereria bancrofti -

adult worm

This study was supported by UNDP/World Bank/WHO Special Program for Research and Trainning in Tropical Diseases (ID 940544), FIOCRUZ (PAPES no. 02) and FACEPE ( no. 0157.2.13/94).

Although Wuchereria bancrofti has been identified in biopsy specimens of lymphatic vessels of the ovary and breast in women and from the scrotal area in men (RR Oliveira, T Caldas 1981 J Bras Ginecol 91: 335-338, P Jungmann et al. 1992 J Trop Med Hyg 95: 114-118, G Dreyer et al. 1994 Trans R Soc Trop Med Hyg 88: 232-236), the distribution of living adult worms within the human body remains poorly defined. F Amaral and colleagues recently showed that ultrasound can be a powerful tool for direct visualization of living adult W. bancrofti in the scrotal area of infected men (1994 Am J Trop Med Hyg 50: 753-757). The characteristic pattern of continuous movement, called the 'filaria dance sign', and the location of the adult worm nests within the lymphatic vessels remain remarkable stable with time (Dreyer et al. 1994 loc. cit. 88: 558). Whether there is a 'preferred' location of W. bancrofti in infected women it remains unknown, although evidence form biopsies of breast nodules suggests that the breast may be an important site of the adult worm in women (Jungmann loc. cit. p. 114-118, H Saxena et al. 1975 Am J Trop Med Hyg 24: 894-896). To determine if live W. bancrofti can be visualized in the female breast by ultrasound, we performed multiple ultrasound examinations (on at least six separate occasions) in seven microfilaremic women at the Filariasis Out Patient Clinic at Centro de Pesquisas Aggeu Magalhaes-FIOCRUZ in Recife, Brazil using a 7.5 MHz transducer (Pie Medical Scanner 200, Rotterdam, the Netherlands). Microfilarial density was determined by filtering 1 ml of blood obtained between 11:00 p.m. and 01:00 a.m. The blood was filtered through a 3 mm Nuclepore filter (Nuclepore Corporation®, Pleasanton, CA) and the slide was stained and examined microscopically. Informed consent was obtained from all patients before participation in the study.

Mean age was 25.9 years (range 17-47). None of the seven women reported symptoms of filariasis or symptoms related to the breast, and none had been previously treated with antifilarial drugs. Physical examinations were unremarkable. Microfilarial density ranged from 85 to 2980 (geometric mean, 316) microfilariae per ml. The filaria dance sign was detected in the left breast of one woman. She was 29 years old and had microfilarial density of 2980 microfilariae per ml. The location of the adult worm nest and their pattern of movement remained consistent each time the patient was examined. In the area where the living adult worms were seen the diameter of the lymphatic vessel was 10 mm. This was the only ultrasound in which lymphangiectasia was detected; ultrasound of the remainig six women were unremarkable. All patients are assisted by the Filariasis Patient Out Clinic and will follow the treatment schedule with diethylcarbamazine (DEC) advised by World Health Organization.

Although the number of patients in this study was small, the proportion of microfilaremic women with detectable filaria dance sign in the breast appears to be relatively low. In contrast, local adverse reaction associated with death of adult W. bancrofti after treatment with DEC are usually limited to the scrotal area in men (Dreyer loc. cit. 88: 232-236, Dreyer et al. 1994 loc. cit. 89: 98-102). In fact, 80% of 100 microfilaremic men in Recife had living adult worms detectable in the lymphatic vessels of the spermatic cord (J Norões 1995 Trans R Soc Trop Med Hyg in press). Thus, it seems that the scrotal area may be the principal site of W. bancrofti in men. We do not yet know whether this difference is because ultrasonographic visualization of the adult worm is more difficult in the breast or because adult worms localize less frequently in women breast than they do in men scrotal lymphatic. Furthermore with a 7.5 MHz transducer, the filaria dance sing cannot be reliably detected in lymphatic vessels of scrotal area < 1 mm in diameter (G Dreyer et al. 1995 loc. cit. 89: 225-226). The same limitations may occur with the filaria dance in the breast.

To our knowledge, this is the first direct observation of living adult W. bancrofti in the female breast reported. Additional work is needed to determine the distribution and location of the living adult worms in women and children. Ultrasound, which has proved to be a useful tool for detection W. bancrofti in the scrotal area of infected men (Amaral loc. cit. p.753-757, Dreyer et al. 1994 loc. cit. 88: 558, Dreyer et al. 1995 loc. cit. 89: 225-226), may also be useful visualizing the live adult worms in women.

Acknowledgements: to the women who participated in the study.

Received 20 June 1995

Accepted 5 October 1995

Copyright 1995 Fundacao Oswaldo Cruz