Global.health in Action: Two Outbreaks, One Response
Over the past four years, the Global.health brand has grown to be a trusted source of data for emergent outbreaks including COVID-19, Mpox, Ebola, and Marburg, supporting international and national health organizations in early risk assessment and public health interventions. We remain focused on our mission to enable rapid sharing of trusted public health data during the early phase of an outbreak, for the first 100 days, to advance the response to infectious diseases.
In 2024, we faced a new challenge—managing data for two major outbreaks simultaneously: avian influenza (H5N1) and Mpox. Our team rose to the occasion, leveraging our infrastructure, network, and experience to enhance global response efforts.
Avian Influenza (H5N1) Outbreak in the United States (U.S.)
In March 2024, the H5N1 avian influenza virus was detected in dairy cattle in the U.S. for the first time, quickly evolving into a multi-state outbreak. Avian influenza infections were also reported in poultry farms. Both U.S. cattle and poultry infections may be attributed to wild bird spillover events. Human cases were soon detected among workers at affected farms, sparking concerns about zoonotic transmission. This event marked the first instance of cow-to-human spread of bird flu globally. By December 2024, there have been 63 confirmed human cases across 10 states from exposure associated with commercial agriculture and related operations. CDC has confirmed an additional three cases, 66 total human cases during the 2024 outbreak. One human case is from other animal exposure (i.e. backyard flocks, wild birds, or other mammals). And the exposure of two human cases are unknown, pushing public health officials to investigate how avian influenza may be spreading beyond farms.
This outbreak evolved our curation strategy, beyond epidemiological data, to launch a One-health surveillance approach that would capture the interconnectedness of humans, animals, and our shared environment [CDC]. In collaboration with ThinkGlobalHealth.org, we have combined epidemiological data for human cases, animal health outbreak data, genomic data, wastewater data, and response and research highlights into one, easy-to-digest, openly-accessible timeline. The Global.health team created over 500 timeline entries, which are organized by topic, for public health authorities to make informed decisions about response and intervention strategies. This is a new approach for us, and we see potential to explore other data sources including climate, environment, socio-economic, and social factors like behavior and mobility that may influence outbreak dynamics.
This avian influenza outbreak in the U.S. has implications for both humans and animals.
As avian influenza infects more people, experts have raised concern over risk for mutation or viral reassortment through co-infection with the seasonal flu to create a viral strain that is transmissible between humans. Although the seasonal flu vaccine is not effective against avian influenza, it is important for individuals, especially farm workers, to get their seasonal flu shots to reduce the risk of co-infection. Influenza virus and illness activity is monitored year-round by the CDC and its vast partner network. All novel influenza A virus infections, different from circulating seasonal human influenza viruses, are nationally reportable. Also, although we have seen mostly mild illness among infected individuals in the U.S., severe cases and deaths have occurred this year around the world. Since the beginning of 2024, Global.health has tracked 108 confirmed human cases, 8 deaths, in 10 countries attributed to 6 viral strains of low and highly pathogenic avian influenza, globally. Therefore, individuals, farms, and authorities must take precautions to protect humans from the virus and reduce pandemic risk.
Among animals, avian influenza has caused widespread illness and death in U.S. cattle and poultry, devastating these industries. From March through December 2024, 915 commercial dairy farms in 16 states have tested positive for avian influenza. H5N1 often manifests in decreased milk production. This coupled with federal and state limitations on cattle movement can have economic impacts. Fortunately, most cows recover from the illness, and the mortality rate is around 2%. However, the virus is extremely deadly in birds, and farms have culled birds to stop the spread. The outbreak has impacted 159 commercial poultry farms in 28 states since March 2024. Over 22.37 million birds in both commercial poultry and backyard flocks are estimated to have been affected. As a result, the USDA projects lower egg production and higher egg prices. To curb the spread of avian influenza among animals, HHS announced over $101 million in funding to address H5N1. USDA also began the National Milk Testing Strategy under a new federal order requiring the collection and testing of raw milk nationwide. Additionally, the USDA has authorized the start of field studies to evaluate the safety and efficacy of HPAI H5N1 vaccines in livestock. In the meantime, the testing and monitoring of these animals are important for early intervention and to curb disease spread.
Mpox (Monkeypox) Resurgence in Africa
Following a surge in mpox cases in the Democratic Republic of the Congo (DRC) and the detection of a new variant of clade 1 mpox virus (MPXV), on 13 August 2024, the Africa Centres for Disease Control and Prevention declared mpox a public health emergency of continental security (PHECS) in Africa. This marked the first time the agency has ever declared a PHECS and unlocked resources and funding, enhanced strategies, and strengthened response capacities. The next day, the WHO Director General determined that the surge in cases in the DRC and spread to other African countries constituted a public health emergency of international concern (PHEIC). With the PHEIC, as we saw with the 2022 global outbreak, media attention and public concern grew.
In our increasingly interconnected and globalized society, outbreaks may have pandemic potential. For that reason, robust, reliable, real-time data is more important than ever. Global.health responded to the PHEIC and released a public dataset and repository for mpox cases on August 29th (retroactively loaded case data from January 2024). As of December 2024, we have hand-curated over 57,000 suspected and confirmed mpox cases in our dataset.
There are two clades of the mpox virus: clades I and II. Both of these clades are endemic to regions in Africa. However, in recent years, there have been significant global outbreaks caused by each clade and its subclades. Global.health tracked the 2022 global outbreak and is once again tracking cases to follow the 2024 surge. These events have been curated as two separate mpox datasets.
2022: Clade II, West Africa, multi-country outbreak in 2022
Historically endemic to West Africa, clade II mpox began spreading to non-endemic regions of the world, including Europe and the Americas in May 2022. Shortly after the outbreak began to spread, a PHEIC was declared in July. Over 120 countries were affected with over 100,000 laboratory confirmed cases reported. The PHEIC lasted for one year, ending in May 2023, but Clade II mpox continues to spread at low levels globally. While clade II is considered less severe compared to clade I, this lineage demonstrated increased transmissibility, with its spread primarily being driven by sexual transmission of the virus among men who have sex with men.
2024: Clade I, Central Africa, Democratic Republic of the Congo (DRC)
Clade I MPXV is endemic to Central Africa. Concerns grew after 2023 marked the highest number of annual cases ever reported in the DRC and the outbreak carried into 2024. Later, in June 2024, a new variant was described, Clade 1b MPXV, and observed sustained human-to-human transmission without suspected animal exposure. The variant was estimated to have emerged around mid-September 2023, coinciding with the initial surge in cases. The new variant has since been detected across nations neighboring the DRC in Africa, including Burundi, Uganda, Rwanda, Kenya, Zimbabwe, and Zambia. As of 18th December 2024, seven other countries outside Africa have reported (imported) cases of mpox clade 1b, including Thailand, Sweden, India, Germany, the U.S., Canada, and the United Kingdom. Ongoing research aims to better understand this clade’s dynamics of transmission, severity, and observations among vulnerable groups, including children.
The DRC is the epicenter of the mpox outbreak; the WHO (data as of 17 November) has reported 43,862 (34,349 suspected and 9,513 confirmed) cases and 1,138 total deaths. The number of deaths from this outbreak is very high when you compare deaths to the 2022 outbreak, which only totaled 220 confirmed deaths. And these counts are likely an underestimate, as many cases that are clinically compatible with mpox will remain untested in the DRC due to limited diagnostic capacity and surveillance in low-resource settings.
Curbing spread is not easy as the DRC faces a humanitarian crisis with many complications including war, internally displaced persons, trades of sex workers, transient populations near border regions, and entrenched poverty in a resource-poor setting and remote locations. While several vaccines are now available to help prevent mpox among adults (children are not currently eligible), there are a limited number of vaccine doses available in these areas. Higher income countries have pledged to provide millions of doses to affected areas. These challenges emphasize the need for a comprehensive and coordinated public health response to mitigate the impact of this outbreak globally.
Outbreak Resources
We tracked two outbreaks with one approach to deliver trusted data during the early phase of an outbreak. The G.h system and methods have proven to be flexible and scalable to support any pathogen, any outbreak. We continue to face challenges associated with building an emerging disease outbreak dataset in real-time, and are constantly learning, reflecting, and honing our curation skills.
On December 7th, we reached 100 days of active outbreak response for mpox and will transition to offer outbreak resources available from the WHO and Africa CDC through our platform. We aim to complement, not replace, existing systems. Users may also access archives for the G.h linelist and briefing reports, here. The avian influenza outbreak timeline will continue into 2025.
As we continue our mission to provide early outbreak data, we encourage health professionals, researchers, and organizations to engage with our platform. We support a transparent, crowdsourced approach to sharing outbreak information across borders and welcome meaningful collaboration and fact checks through GitHub. Get involved!
Until the next post,
The G.h Team