In 2011, Public Health England reported an increase in UK acquired cases of Shigella flexneri among MSM in the Greater Manchester area in July, 2011 and in London in 2010/2011¹. In April, 2015, a report by Simms et al suggested that there has been an intensification of sexually transmitted shigellosis among men who have sex with men (MSM). This could account for up to 97%, 89% and 43% of non-travel associated S. flexneri 3a, S. flexneri 2a and S. sonnei cases in the U.K. in 2014².

Preliminary analysis of Irish data for the period 2010 to week 25, 2015, indicates that there is a male excess in non-travel related cases of S. flexneri and S. sonnei.  Overall the male-to-female ratio for this period was 2.6 but jumped to 7.0 and 8.0 in 2014 and 2015 (weeks 1-25), respectively. Similar to the situation in London, Manchester and Brighton², there is an excess of S. flexneri 2a and S. sonnei respectively in HSE East which has a larger MSM population than other parts of the country.

The Department of Public Health in HSE East has prepared a protocol for investigation, control and surveillance of shigellosis cases in men. This ensures that cases identified as sexually-acquired are provided with further advice in addition to the routine advice for gastroenteric illnesses, either by a doctor in HSE East or by their own GP. This includes recommending an STI screening and partner notification³.

The Department of Public Health, HSE East, the HSE Gay Men’s Health Service (GMHS), Gay Health Network (GHN) and HPSC have produced health promotion materials targeting MSM which are available at www.man2man.ie.

Since the end of September, 2015, there have been 10 confirmed cases of shigella infection notified in the greater Dublin area among people who have not travelled to Shigella spp.-endemic countries, and of these 9 are MSM. Cases have presented with symptoms of gastroenteritis, some of whom have been managed in primary care and others have required hospital admission with symptoms suggestive of inflammatory bowel disease. Some cases are also HIV positive.

An Outbreak Control Team (OCT) has been established by the Department of Public Health in Dublin. In addition to the measures listed below, the OCT is also recommending that all shigella cases that may be associated with this outbreak be treated with appropriate antibiotics in order to reduce shedding time, thereby reducing the risk of onward transmission. When empirical antimicrobial therapy is indicated, ciprofloxacin 500mg every 12 hours PO for 3 days may be used although it should be noted that ciprofloxacin resistant strains of Shigella sonnei have been identified in Ireland. Azithromycin 500mg daily for 3 days is an alternative. Antimicrobial susceptibility test results should be used to guide therapy when available. 

Measures to prevent onward transmission of shigellosis among MSM

• Clinicians should consider the possibility of shigellosis in MSM who present with gastroenteritis.
• Patients should be reminded of the importance of safer sex practices and regular STI testing for those at risk of STIs. Further information and detail of services  for MSM are available at www.man2man.ie
• Clinicians should notify any cases of shigella to their local Director of Public Health 

Gillian Cullen, HPSC; Dr Derval Igoe, HPSC, Mick Quinlan, Gay Men’s Health Service & Dr Fionnuala Cooney, Dept. of Public Health HSE East (Chair) on behalf of the Shigella Outbreak Control Team

References

1. Ongoing outbreak of Shigella flexneri in men who have sex with men, England and Wales, 2011/12: interim findings. Health Protection Report 6(14), 12 April 2012.
2. Simms I, Field N, Jenkins C, Childs T, Gilbart VL, Dallman TJ, Mook P, Crook PD, Hughes G. Intensified shigellosis epidemic associated with sexual transmission in men who have sex with men - Shigella flexneri and S. sonnei in England, 2004 to end of February 2015. Euro Surveill. 015;20(15):pii=21097. Available here. 
3. Protocol in shigellosis notifications. HSE Department of Public Health East, June 2015