Postpartum genital myiasis – Dermatobia hominis infestation with giant uterine fibroid: A rare case with review of literature

Abstract

A 32-year-old multiparous rural woman having 26 weeks of pregnancy with giant uterine fibroid extending up to the cervix had stillbirth 2 weeks back and left hospital against medical advice. She was readmitted in emergency with necrotic prolapsed uterine fibroid with offensive vaginal bleeding. On examination, the patient had necrotic prolapsed fibroid with very offensive bloody discharge and a large number of larvae of Dermatobia hominis (human botfly) were crawling in necrotic tissue. The location of this infestation at genital region is an extremely rare occurrence in postdelivery patients.

INTRODUCTION

Myiasis is derived from Greek word, Myia which means fly.[1] Myiasis is the infestation by dipterous larvae or maggots of various fly species of veterinary and medical interest which feed on living or necrotic tissue of the host which causes secondary bacterial infections. Cutaneous, nasopharyngeal, ophthalmic myiasis is common.[2] Genital myiasis is a rare condition. The infestations reduce host physiological functions, destroy host tissues, and cause significant economical losses.[1] We report a case of genital myiasis in a postdelivery patient with giant uterine fibroid which was infested by Dermatobia hominis (human botfly) larvae.

CASE REPORT

A 32-year-old female, multiparous, an agriculturalist from rural background, presented with a history of some blood-stained masses coming out through vagina with very offensive odor. History revealed that she was hospitalized 20 days back in the same hospital with complaints of abdominal pain and bleeding pervagina; she had 6 months of pregnancy with uterine fibroid. On ultrasonography (USG) examination, a large heterogeneous echogenic mass was noticed in the pelvic cavity, which was extending up to epigastric region and it measured approximately 17.3 cm × 14.2 cm, 6-month-old dead fetus along with bilateral mild hydroureteronephrosis changes. Magnetic resonance imaging revealed uterine fibroid measuring 14 cm × 15 cm × 22.6 cm in uterine cavity with mild-to-moderate bilateral hydronephrosis.

Past reports during her antenatal visits and old USG reports done at 13 weeks of pregnancy confirmed that she had single live intrauterine fetus with a large isoechoic lesion along anterior aspect of the cervix with increased vascularity and causing stretching of cervix (measuring 9 cm × 11 cm × 15 cm in size) with cranial displacement of uterine corpus. At 26 weeks of pregnancy, she was admitted with abdominal pain and bleeding pervagina and delivered 26 weeks dead fetus. She was managed with antibiotics, tablet iron, tablet calcium and blood transfusion was done due to bleeding pervagina but she left hospital against medical advice.

After 15 days, the patient was rehospitalized; she had very offensive discharge and a blood-stained mass was coming out from the vagina. When pervaginal examination was done, a large number of larvae were crawling out from the vagina in the necrotic tissue [Figure 1]. Her personal history revealed that she was used to go in open field for defecation and did not take bath for several days after delivery as a ritual present in Western Rajasthan. The patient reported that she used dirty clothes and reused them after washing instead of using good-quality sanitary napkins. As this patient delivered in rainy season, she reused clothes after washing and probably she used moist clothes. Perhaps this attracted the flies and they laid eggs on the reused damped clothes which were used by the patient.

Figure 1.

Patient pic with necrotic tissue, bloody discharge and large number of larvae are seen

On routine investigations, her reports were in normal range; venereal disease research laboratory test, HIV, hepatitis B virus surface antigen, and hepatitis C virus all tests were negative. Necrotic tissue and urine samples were received in microbiology laboratory for culture and sensitivity and identification of larvae [Figures 2–4]. In urine sample Escherichia coli was grown which was found sensitive with Piperacillin -tazobactam and Imipenem.

Figure 2.

Larvae of Dermatobia hominis

Figure 4.

Larvae of Dermatobia hominis under × 10

Figure 3.

Larvae of Dermatobia hominis under × 10

Necrotic tissue was kept in a sterile Petri Dish and a large number of milky white larvae were crawling in the necrotic tissue[Figure 5]. Microscopic examination of larvae was done under ×10 to visualize all body parts, head, body, and tail parts [Figures 2–4]. On the basis of morphology, it was identified as larvae of D. hominis.

Figure 5.

Larvae of Dermatobia hominis crawling on the necrotic tissue

The patient was dressed with povidone iodine locally along with injection pip-tazo was given as an antibiotic. Despite medical treatment, the patient did not improve. Dilatation and curettage was done; on examination, a large number of larvae were seen. As the patient did not response to medical treatment, hysterectomy was done.

Discussion and review of literature

Myiasis is defined as the infestation of live human and vertebrate animals by larvae of varied species.[2] Myiasis is derived from the Greek word “Myia,” meaning “fly.” The term was first introduced by hope in 1840 and refers to the infestation of human beings with dipterous larvae (maggots). The word maggots means larva of the fly. It is the nontechnical word and the technical term is myiasis, which is defined as a disease caused by the infiltration of body tissue by house fly's larva.[3] Maggots like fly larvae are of wide importance in ecology, economy, surgery, and forensic medicine.

The distribution of myiasis is worldwide with more cases being reported from tropical, subtropical, and warm temperate areas.[2] The lack of personal hygiene and sanitary conditions is the contributing factor for the cause of myiasis, more so with the genital.[4,5] Urogenital myiasis involves infestation of the urinary tract, as well as genital organs such as vaginal or penile orifices, with fly larvae. The condition is rare among humans inhabiting developed countries, but relatively more common in patients with low socioeconomic status with poor hygienic conditions in developing countries.[2]

Female flies possibly are attracted by the foul odor and lay eggs in existing lesions. Thereafter, the larvae invade the tissue and feed themselves on living tissues.[6] Larvae usually pupate within 1–2 days and emerge as adult males 6 days later.[7]

Myiasis is the infestation of human or animal tissue by fly larvae, deposited as eggs or first-stage larvae; the larvae developed by feeding on the surrounding tissue emerge as third-stage larvae and pupate in the environment.

There are three forms of myiasis[8]

1. Obligate myiasis reflects the need for larvae to feed well during development because adult flies do not feed or feeds poorly, e.g., D. hominis, Cordylobia anthropophaga[8,9]

2. Facultative myiasis: In it, flies deposit their eggs onto fecal or other rotting organic material or directly lay eggs into wounds or necrotic tissue, but larvae may not confined themselves to such resources and may move to healthy tissue, e.g., Phormia regina, Lucilia sericata, and Musca domestica[8,9]

3. Accidental myiasis: It includes incidental findings of fly larvae, often Musca domestica (common housefly), under wound dressings or within unusual site such as gastrointestinal tract.[8,9]

There are three families of flies encountered in myiasis and can be divided into two groups for comparison of host location strategies.

1. Oestridae: They are obligate parasites; they deposit their eggs or larvae directly onto the host

2. Calliphoridae and Sacrophagidae: They are obligate parasites and primary facultative parasite; they deposit their eggs or larvae directly onto the host at some predisposing sites, such as those caused by wounding and necrosis.[10]

These parasites can be identified by microscopic examination or developing these larvae to adult flies for entomological classification.

The classical description of myiasis is according to the part of the host that is infected.[3,4]

1. Dermal

2. Subdermal

3. Cutaneous

   1. Creeping, where larvae burrow through or under the skin
   2. Furuncular, where a larva remains in one spot, causing a boil-like lesion.

4. Nasopharyngeal nose, sinuses, or pharynx

5. Ophthalmic or ocular in or about the eye

6. Auricular in or about the ear

7. Gastric, rectal, or intestinal/enteric for the appropriate part of the digestive system

8. Urogenital.

Human genital myiasis can be external or internal based on anatomical site, which is affected.[11,12] External genital myiasis is common in females as compared to males. Poor general health and personal hygiene, lower socioeconomic status, psychiatric illness, diabetes mellitus and ulcerative lesions are predisposing factors for genital myiasis.[11] In women cases of genital myiasis are seen in clitoris, urethra, vulva, vagina and uterus.[6] Intestinal myiasis is rare.[11] The pathogenicity results from inflammation and toxins secreted by the larvae. The larvae are photophobic, penetrating deep into the tissues with the help of sharp mouth hooks.[13] Genitourinary infestation usually presents as pain and pruritis at the site.[5,12,14,15]

In present case report patient had post partum genital myiasis. Purnima et al. reported a case of genital myiasis in a woman with uterovaginal prolapse.[11] Baidya reported a case of genital myiasis in a woman with uterovaginal prolapse and vaginal malignancy.[6] Cilla et al. described a case of vulvar myiasis in a diabetic 86-year-old female.[16] Passos et al. reported a case of vulvar myiasis during the pregnancy.[7] Human genital myiasis is usually associated with poor personal hygiene, diabetes mellitus, and ulcerative lesion.[11,15]

The present case was an illiterate, multiparous female from rural background indulged in farming and her personnel hygiene was very poor. She was suffering from giant fibroid uterus for which she was not aware and did not take any treatment though she had four pregnancies (two live and two dead).

Perhaps due to cervical giant fibroid, the patient had continuous bleeding and she used dirty clothes and reused after washing; due to rainy season, used clothes were not dried properly and she reused the same clothes repeatedly. Besides it, there is a ritual in Western Rajasthan that postdelivered mother cannot take bath for 10–15 days and she used open field defecation. Hence, due to poor sanitation and poor hygiene, it attracted flies on the used dirty clothes and laid eggs on it which were reused by the patient and initiated larval development. The possible source in the present case may be the eggs, which were transmitted via the soil and dirty clothes. The same mode of transmission of genital myiasis was reported by Kataria et al., in which they concluded that routine habit among villagers to dry their washed cloths on ground, flies laid eggs on clothes line as flies were attracted to the blood and body secretions.[4]

TREATMENT

Systemic treatment includes broad-spectrum antibiotics after the removal of larvae to help prevent secondary infections.[5,17] Turpentine oil (larvicidal) applied locally is helpful.[11,18,19,20] Surgical excision is also an option, although usually it is not always necessary.[11]

Ivermectin is effective in the treatment of several myiasis and it is a good alternative when surgical removal is unfeasible.[21,22] In all cases of myiasis, avoid breaking the larva. One must remove the entire larva to avoid a hypersensitivity or foreign body reaction to the larval antigens.[23] Facultative myiasis is caused by blow-flies (Phormia, Lucilia, and Musca). Some facultative larvae of Lucilia serrica secrete bacteriolytic enzymes and is used for sterilization of infected wounds![24]

The use of turpentine oil or petroleum jelly produced excellent results as they arrest the larval breathing by hypoxia. Turpentine oil can be used for cutaneous, orbital or external genital myiasis.[24] In the present case turpentine oil couldn't be used as the patient had necrotic giant uterine fibroid. Patient did not improve with medical treatment and hysterectomy was done.

General improvement of sanitation, personal hygiene, and exterminating the flies by insecticide are helpful in prevention. Simple measures such as washing clothes thoroughly and drying and ironing of clothes are also necessary to reduce the risk of this human myiasis.[25]

CONCLUSION

Human genital myiasis can be prevented by use of good quality sanitary napkins and proper counseling about personal health hygiene. If infestation of maggots occurs, the management of the patient with ivermectin and the use of turpentine oil produced excellent results sufficient to stop the further development of maggots into adult form. Mechanical removing of the maggots sometimes results in damage to the larvae with retention of larval fragments in the lesion.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.