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Ignatzschineria indica

UPDATED JANUARY 24, 2022

NCCID Disease Debriefs provide Canadian public health practitioners and clinicians with up-to-date reviews of essential information on prominent infectious diseases for Canadian public health practice. While not a formal literature review, information is gathered from key sources including the Public Health Agency of Canada (PHAC), the USA Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO) and peer-reviewed literature.

This disease debrief was prepared by Tolani Olanrewaju. Questions, comments, and suggestions regarding this disease brief are most welcome and can be sent to nccid@manitoba.ca.

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What are important characteristics of Ignatzschineria indica?

Cause

Ignatzschineria indica (I. indica) infection is caused by myiasis, the infection of human tissue by fly larvae. I. indica is a Gram-negative, aerobic, bacillus, and non-motile bacteria. I. indica belongs to the gammaproteobacterial class, along with three other species: Ignatzschineria larvae, Ignatzschineria ureiclastica, Ignatzschineria cameli. (These species were previously categorized as Schineria). It is transmitted by the larvae (maggots) of flesh flies (Sarcophaginae) and blow flies (Calliphoridae).

Signs and Symptoms

Infected persons will typically present with a maggot-infested wound. Symptoms vary in severity, but can include fever, elevated white blood count, pain, and hypothermia. It is possible to be infected and present with normal vital signs.

Severity and Complications

Mortality rates are not available due to the rarity of the disease. In case reports, outcomes have varied from severe illness and death to full recovery. Comorbidities, time to diagnosis, and other determinants of health may be significant in determining disease progression.

Epidemiology

General:

Cases of Ignatzschineria have been reported in Europe, Canada, and the United States of America. While I. larvae and I. ureiclastica are the dominant species reported in Europe, I. indica is the only species reported in North America.  The infection is quite rare, with 2 confirmed cases in Canada, 8 confirmed cases in Europe and 7 confirmed cases in the United States of America. Unclean living environment, poor social situation, substance use, homelessness and transient lifestyle are the strongest risk factors for I. indica infection.

Clinical and Laboratory Diagnosis:

Tissue culture and PCR are recommended for diagnosis. I. indica has been isolated from blood, urine and breast abscess, and cultured for identification in Muller-Hinton agar, MacConkey agar, Salmonella Shigella agar, brain heart infusion agar, and King’s medium A base agar (HiMedia). In most case reports, cultures displayed multiple microbial results, and organisms belonging to the genus Acinetobacter, Oligella, Alcaligenes, and Psychrobacter have been misidentified as I. indica. As such, confirmation with molecular methods is recommended, particularly 16s RNA amplification and sequencing. Complementary tests could include the Gram test, catalase test and oxidase test. I. indica is Gram-negative, catalase-positive, and oxidase-positive.

Prevention and Control

I. indica is vector-borne; the green bottle fly (Lucilia seracata), and spotted flesh fly (Wohlfahrtia magnifica) are confirmed vectors. Green bottle flies are present in southern Canada, but the spotted flesh fly is not. There is uncertainty about the type of fly larvae that transmits I. indica in Canada. Prevention of infection should focus on improving determinants of health and pathways to care for vulnerable groups, to prevent the development of larvae-infested wounds.

Vaccination

There is no vaccination available against I. indica infection.

Treatment

Clinical specimens of patients presenting with myiasis should be examined for unusual infections, including I. indica. The optimal treatment for I. indica is undefined, but the bacterium has been found to be susceptible to aminoglycosides, trimethoprim-sulfamethoxazole, and fluoroquinolones. Resistance to third-generation cephalosporins, piperacillin–tazobactam, and carbapenems has been described.

Larvae can be removed surgically, or by using a scab brush with the patient under anesthesia.

What is happening with current outbreaks?

Only 2 cases have been reported in Canada: in Ottawa, Ontario (2019) and in Winnipeg, Manitoba (2020). Both cases involved a vulnerable patient presenting with a maggot-infested ulcer.

What is the current risk for Canadians?

The risk is very low in the general population. It is higher in vulnerable populations presenting with myiasis, particularly the elderly, people who use substances, and those living in unsanitary conditions.

What measures should be taken for a suspected case or contact?

There is no reporting protocol for suspected or confirmed cases in Canada.