Investigating the Increase in Group A Streptococcus Among Indigenous Peoples

Invasive group A Streptococcus (iGAS) disease has been on the rise among indigenous populations around the world. Researchers from University of Alberta, Alberta Ministry of Health, both in Edmonton, and Alberta First Nations Information Governance Center in Alberta conducted a study to find out more. Between 2003 and 2017, they investigated iGAS cases among First Nations, Inuit, and Métis members in Alberta.

During that time, 669 cases of iGAS were reported. The incidence increased from 10 cases per 100,000 in 2003 to 52 cases per 100,000 in 2017—an incidence rate > 6 times that of non–First Nations populations. The researchers say the disproportionately high rates are seen in other Native American groups compared with the rates in the general population: One study, for instance, found the incidence rate for Alaska Natives was 13.7 cases per 100,000 compared with 3.9 cases per 100,000 for non–Alaska Natives.

What’s driving the higher rates isn’t completely clear, the researchers say. They note that risk factor data in their study “frequently” indicated nonsurgical wounds, addiction abuse, and homelessness. They also cite research that has found skin infections and skin breakdown are common among iGAS patients who were injection drug users or homeless. Diabetes mellitus—rampant among Native Americans—was another risk factor.

The researchers found a “striking difference” in that the First Nations members had more skin and soft tissue infections and, unexpectedly, fewer streptococcal toxic shock syndrome cases than did the non–First Nations groups.

Moreover, skin-to-skin transmission may be more common than respiratory transmission: When they grouped emm types (the bacteria are typed according to a protein encoded by the emm gene) by cluster, they found the bulk of disease among the First Nations population was associated with skin-related infections, not throat-related clusters. This may be a consequence of overcrowded households or inadequate housing, both issues for Native American communities. The researchers say emm59, the most prevalent emm type in the First Nations population in the study, displays a tropism for skin infections. Since 2006, they add, when a large outbreak of emm59 was reported, it has become common throughout western Canada and the US, where it had previously been relatively rare.

Of note, the researchers conclude, substantial emm differences could have potential implications for future vaccine.

Source: Tyrrell GJ, Bell B, Bill L, Fathima S. Increasing incidence of invasive group A Streptococcus Disease in First Nations population, Alberta, Canada, 2003-2017. Emerg Infect Dis. 2021;27(2):443-451. doi:doi:10.3201/eid2702.20194

Invasive group A Streptococcus (iGAS) disease has been on the rise among indigenous populations around the world. Researchers from University of Alberta, Alberta Ministry of Health, both in Edmonton, and Alberta First Nations Information Governance Center in Alberta conducted a study to find out more. Between 2003 and 2017, they investigated iGAS cases among First Nations, Inuit, and Métis members in Alberta.

During that time, 669 cases of iGAS were reported. The incidence increased from 10 cases per 100,000 in 2003 to 52 cases per 100,000 in 2017—an incidence rate > 6 times that of non–First Nations populations. The researchers say the disproportionately high rates are seen in other Native American groups compared with the rates in the general population: One study, for instance, found the incidence rate for Alaska Natives was 13.7 cases per 100,000 compared with 3.9 cases per 100,000 for non–Alaska Natives.

What’s driving the higher rates isn’t completely clear, the researchers say. They note that risk factor data in their study “frequently” indicated nonsurgical wounds, addiction abuse, and homelessness. They also cite research that has found skin infections and skin breakdown are common among iGAS patients who were injection drug users or homeless. Diabetes mellitus—rampant among Native Americans—was another risk factor.

The researchers found a “striking difference” in that the First Nations members had more skin and soft tissue infections and, unexpectedly, fewer streptococcal toxic shock syndrome cases than did the non–First Nations groups.

Moreover, skin-to-skin transmission may be more common than respiratory transmission: When they grouped emm types (the bacteria are typed according to a protein encoded by the emm gene) by cluster, they found the bulk of disease among the First Nations population was associated with skin-related infections, not throat-related clusters. This may be a consequence of overcrowded households or inadequate housing, both issues for Native American communities. The researchers say emm59, the most prevalent emm type in the First Nations population in the study, displays a tropism for skin infections. Since 2006, they add, when a large outbreak of emm59 was reported, it has become common throughout western Canada and the US, where it had previously been relatively rare.

Of note, the researchers conclude, substantial emm differences could have potential implications for future vaccine.

Source: Tyrrell GJ, Bell B, Bill L, Fathima S. Increasing incidence of invasive group A Streptococcus Disease in First Nations population, Alberta, Canada, 2003-2017. Emerg Infect Dis. 2021;27(2):443-451. doi:doi:10.3201/eid2702.20194

Invasive group A Streptococcus (iGAS) disease has been on the rise among indigenous populations around the world. Researchers from University of Alberta, Alberta Ministry of Health, both in Edmonton, and Alberta First Nations Information Governance Center in Alberta conducted a study to find out more. Between 2003 and 2017, they investigated iGAS cases among First Nations, Inuit, and Métis members in Alberta.

During that time, 669 cases of iGAS were reported. The incidence increased from 10 cases per 100,000 in 2003 to 52 cases per 100,000 in 2017—an incidence rate > 6 times that of non–First Nations populations. The researchers say the disproportionately high rates are seen in other Native American groups compared with the rates in the general population: One study, for instance, found the incidence rate for Alaska Natives was 13.7 cases per 100,000 compared with 3.9 cases per 100,000 for non–Alaska Natives.

What’s driving the higher rates isn’t completely clear, the researchers say. They note that risk factor data in their study “frequently” indicated nonsurgical wounds, addiction abuse, and homelessness. They also cite research that has found skin infections and skin breakdown are common among iGAS patients who were injection drug users or homeless. Diabetes mellitus—rampant among Native Americans—was another risk factor.

The researchers found a “striking difference” in that the First Nations members had more skin and soft tissue infections and, unexpectedly, fewer streptococcal toxic shock syndrome cases than did the non–First Nations groups.

Moreover, skin-to-skin transmission may be more common than respiratory transmission: When they grouped emm types (the bacteria are typed according to a protein encoded by the emm gene) by cluster, they found the bulk of disease among the First Nations population was associated with skin-related infections, not throat-related clusters. This may be a consequence of overcrowded households or inadequate housing, both issues for Native American communities. The researchers say emm59, the most prevalent emm type in the First Nations population in the study, displays a tropism for skin infections. Since 2006, they add, when a large outbreak of emm59 was reported, it has become common throughout western Canada and the US, where it had previously been relatively rare.

Of note, the researchers conclude, substantial emm differences could have potential implications for future vaccine.

Source: Tyrrell GJ, Bell B, Bill L, Fathima S. Increasing incidence of invasive group A Streptococcus Disease in First Nations population, Alberta, Canada, 2003-2017. Emerg Infect Dis. 2021;27(2):443-451. doi:doi:10.3201/eid2702.20194