The importance of listing Strep A as a Neglected Tropical Disease

Strep A, which can lead to serious illness and death if untreated, should be recognised as a Neglected Tropical Disease according to a leading infectious disease expert.

Professor Michael Good AO, Principal Research Leader at Griffith University’s Institute for Glycomics, authored a paper published this week in PLOS Neglected Tropical Diseases.

Neglected tropical diseases (NTDs) are a heterogeneous group of diseases that affect some of the poorest people on the planet. They occur predominantly in low- and middle-income tropical countries (LMIC) and among indigenous and very poor people living in developed countries.

“Although Strep A (Streptococcus pyogenes, group A streptococcus) causes multiple non-life-threatening diseases like tonsillitis and pyoderma, it can also lead to potentially deadly illnesses such as Rheumatic fever (RF), rheumatic heart disease (RHD), and invasive streptococcal disease (ISD),” Professor Good said.

“ISD can follow seemingly mild Strep A infections and quickly lead to necrotising fasciitis and toxic shock, with mortality rates reported between 20% and 50%.

“At risk groups include indigenous populations within developed countries, people who are homeless or with other measures of disadvantage, and the very young or elderly in developing nations.”

Strep A bacteria growing on ‘blood agar’ in a Petri dish

Globally, the total number of deaths attributed to diseases caused by Strep A (principally RHD and ISD) is estimated to exceed 500,000 per annum, with the greatest impact being in LMICs.

“Studies show us that, like the accredited NTDs, Strep A diseases are not restricted to tropical countries but closely follow poverty,” Professor Good said.

History shows that Strep A diseases are amenable to control by combining appropriate penicillin use with accurate laboratory-supported diagnosis and first-rate public health.

The development of a vaccine against Strep A is required for further control and elimination of more serious diseases like RHD and ISD.

“While there may be no definition for “neglected” in terms of research, it is evident from publicly available funding and clinical trial activity that Strep A research is supported far less than research in other diseases with a similar geographical footprint and with a similar level of global disease burden. The level of research activity is similar to the level of activity for the accredited NTDs.

“Listing serious Strep A disease as an NTD will bring it under the umbrella of organisations whose mission is to encourage investment from all sectors to control and eliminate these diseases.

“Their formal inclusion will enhance political, organisational, and societal pressure and will hasten the commitment of industry and lead to the ultimate elimination of these diseases.”