Vulvo-vaginal myiasis among rural women in West Bengal, India

Myiasis, the infestation of living or dead tissue of vertebrates by larvae (maggots) of dipterous flies, is well-known in the medical field. Different parts of the human body, such as skin, oral, nasal, urogenital are affected and named accordingly. The present study was a clinic-entomological study where the women having vulvo-vaginal myiasis were included. Maggots were collected, cultured, and adult flies were identified. A total of 34 cases of vulvo-vaginal myiasis were treated. The larvae of 29 cases were cultured into adults. Most of the women are rural (94%), illiterate and from a low socioeconomic society. The authors specified the infested sites of vulva and vagina such as vaginal, labia, clitoris, episiotomy wound, vulval growth, and prolapsed uterus. The episiotomy wound (32%) is the most common infestation site, followed by the vagina (26%). Chrysomya bezziana (76%) and Chrysomya megacephala (24%) are the identified flies. Illiterate, rural puerperal mothers of low socioeconomic status without proper health education and basic hygiene knowledge are vulnerable to myiasis.


Introduction Introduction Introduction Introduction
Myiasis is a zoonotic disease in which larvae (maggots) of the dipterous fly infest humans and vertebrates' dead or healthy tissue (Smith, 1986;Robbins and Khachemoune, 2010). Different parts of the human body, such as skin, oral, nasal, urogenital are affected and named accordingly. The most prevalent site of infestation is the skin (Caumes et al., 1995), while the genitourinary region is the least common (Francesconi and Lupi, 2012). Human myiasis is of great veterinary importance but most health care professionals often consider myiasis as a minor clinical entity and report intermittently, limiting clinical details and patient characteristics in the academic field (Robbins and Khachemoune, 2010). It is relatively less studied and the data up to species level identification is often unavailable on human myiasis. Although maggot culture is frequently used in the AcademicPres Notulae Scientia Biologicae treatment of patients, species identification is not part of medical therapy (Fonseca-Muoz et al., 2020).
Identification of maggots is helpful in determining the timing of infestation, clinical outcome, and place of infestation (Sherman, 2000). Species identification requiring adult fly is to estimate the timing and circumstances of maggot infestation more specifically, as some species have a characteristic life cycle different from others of the same family, addiction to host and type of tissue, living or dead (Sherman, 2000;Beyramysoltan et al., 2020). Moreover, Vulvar myiasis is a rare disease that accounts for only 0.7% of human infestations (Sherman, 2000). In Ecuador, it varies from 4.7 to 23/100,000 population according to the region (Calvopina et al., 2020). A number of unusual cases of vaginal myiasis have been reported around the world: USA (Bury et al., 1979); Hong Kong (Chan et al., 2005); Japan (Chigusa et al., 2005); Brazil (Garbeloto et al., 2013); UK (Soulsby et al., 2016); and India (Gupta et al., 2014;Mondal et al., 2016;Paul et al., 2021). The current study was a clinico-entomological investigation into vulvo-vaginal myiasis in the Bankura district of West Bengal, India, where it has the potential to become the most frequent personal hygiene-associated skin disease, with more species and greater abundance in lower socioeconomic regions.

Materials and Methods Materials and Methods Materials and Methods Materials and Methods
Several cases of vaginal myiasis were reported from different parts of the Bankura District, West Bengal, India. Three rural hospitals in Bankura district were requested to take part in the study. Female patients with vulvo-vaginal myiasis were included in the present study between January, 2017 and December, 2019. Each woman was placed in a lithotomy position and vulvo-vaginal regions were examined by the respective gynecologist. Vagina, labia and clitoris were thoroughly searched for maggots and burrows. Visible maggots were grasped carefully by forceps and hidden maggots were collected during subsequent dressings. Ether, routinely used to kill maggots in many hospitals, was not used during the present study to collect live maggots. Collected maggots were kept in properly labeled bottles filled with fresh raw chicken meat pieces for transportation. Wounds were cleaned with a saline-antibiotic solution and maggots were removed during subsequent dressing if detected. Oral antibiotics and analgesics were prescribed.
After the collection of maggots from every patient, the consent form, labeled bottle and the examination sheet containing details of the patient and clinical findings were sent to the entomology laboratory of Sonamukhi College, where maggots were photographed. Again, fresh raw chicken meat was used as a culture medium for the maggots. After attaining the third instar stage on rearing material, the matured and sluggish maggots were transferred to another culture jar containing moist saw dust, where the maggots transformed into pupae. After six days (Average temp. 34 °C and RH 72%) of pupation, adult flies were emerged out. The authors (SM, PH, and SKS) identified the emerged adult flies up to species level by studying morphological characteristics following Senior-White et al. (1940) and Smith (1986).

Results Results Results
Over the three-year period, a total of 34 patients fulfilled the selection criteria. Most of them are poor (91%), illiterate (79%), and rural women (94%) of Bankura district (Table 1). Maggots from all cases had been collected and brought to the entomological laboratory, where successful rearing was possible in 29 (85%) cases. Maggots of five cases (15%) died during the rearing process, which could be due to use of certain chemicals on the patients before admission to the hospital. Most of the women (76%) were affected between the ages of 26 and 49 years, whereas only six women (18%) were between 15 and 25 years. Two women above 50 years were also affected (Table 1).  (79) During puerperium, 11 (32%) lactating mothers suffered the infestation at the episiotomy wound. Infestation of maggots was seen in nine cases in the vagina (26%), five cases in labia minora and clitoris (15%), four cases in labia majora (12%), and only three cases in labia minora (9%) ( Table 2). Infestation of women above 60 years was in the prolapsed vagina and vulval growth (Figure 1). The vulval growth was later diagnosed as squamous cell carcinoma. Among the 29 flies grown in the laboratory, 22 were Old World Screwworm Chrysomya bezziana, and seven were Latrine fly Chrysomya megacephala (Table 3, Figure 2). Five larva was dead, and could not be grown, was from Chrysomya bezziana. Interestingly, Chrysomya megacephala affected all age groups in the study, but Chrysomya megacephala affected mainly puerperal cases in the infected episiotomy wounds.

Discussion Discussion Discussion
A total of 34 women were from rural areas between 15 and 50 years of age and from low socioeconomic status, having poor hygiene and low literacy levels (Table 1). However, no age group is immune to infestation (Ziaei Hezarjaribi et al., 2014). Myiasis of exposed wounds can be explained by direct deposition of eggs by adult flies as flies are attracted by the smell of blood (Kataria et al., 2013) but the covered vulval region is affected rarely. The mode of egg deposition is really surprising. Women from rural areas of Bankura district usually do not use undergarments and sanitary napkins during menstruation. They use clothes like handkerchief-size and shape to cover the vulva antero-posteriorly as a menstrual blood absorbent. The clothes are washed and dried in the open air for reuse. Blood mixed clothes attract flies for egg deposition (Kataria et al., 2013).
Episiotomy wound was the single most common site of infection (32%) in the present study ( Table 2). The creeping sensation, visible maggots and disruption of wounds are psychologically traumatic for young mothers during their glorious moments of life. Rural women are ignorant of episiotomy wound care after discharge from the hospital. Infected wounds soaked with fowl smelling lochia may attract flies for deposition of eggs while defecating in the field. Egg deposition could have been through the clothes used for covering the vulva or directly during sitting open. Dohiya and Khosla (2002) reported three cases of vulval myiasis due to home delivery by traditional birth attendants (Dahiya and Khosla, 2002). However, in the present study, all mothers (11 of 34 cases) were delivered at hospitals and discharged after 48 hours. Inoculation might be at home due to poor hygiene and lack of health consciousness.
Vulval myiasis is so rare that its classification has not been documented depending upon the structures involved such as vagina, labia, clitoris, or any wound (ulcers, cancerous growth). Among the cases, labia (majus and minus) with clitoris are the predominant site of infestation (36%), followed by episiotomy wounds (32%) ( Table 2). Maggots were recovered from the vaginal canal of nine women (26%). Accompanied by burrowing lesions, these cases are called vaginal myiasis (Figure 1). Long-standing untreated huge utero-vaginal prolapse often results in decubitus or venous ulcers. Elderly village women are bound to support the prolapse by binding the vulva antero-posteriorly with clothes. The study reports myiasis in a vulval growth which was later diagnosed as vulval carcinoma.
No deaths were reported during the study period. All the women were relieved with dressing. However, surgical intervention was required for resuturing episiotomy wounds in all cases for the restoration of vulval anatomy and coital function. Radical vulvectomy was done in one case of vulval cancer. The women having long-standing genital prolapse got the definitive care, vaginal hysterectomy with apical suspension and pelvic floor reconstruction following healing of ulcer. Saldarriaga et al. (2011) reported a similar case of myiasis in genital prolapse due to personal neglect and poor hygiene. Ivermectin was used in the case. Only four cases have been reported in the literature.
Among Bengal, India and also highlighted the importance of maintaining personal hygiene to avoid larval infestations.

Conclusions Conclusions Conclusions Conclusions
The incidence of vulvo-vaginal myiasis is likely to be underestimated as it is occasionally documented in case reports. Even though this type of report is documented in the health center, most women refuse infectious tissue and maggots to be collected for further examination. They usually avoid talking about the issue with researchers. Rural, poor, illiterate women having limited experience of maintaining genital hygiene are the most vulnerable group. Health education about episiotomy wound care and the supply of sanitary napkins during discharge of lactating mothers following vaginal deliveries could be of paramount help in reducing episiotomy wound myiasis. Furthermore, more focus must be given to sharing the knowledge gained from this type of cases to illiterate and tribal women in order to maintain good personal hygiene. Ethical approval Ethical approval Ethical approval Ethical approval

Authors' Contributions Authors' Contributions Authors' Contributions
The study was approved by the Research Ethics Committee of Bankura Sammilani Medical College, Bankura, West Bengal, India. Written consent for participation in the present study and the culture of maggots was taken from the patients.