Deadly Disease Claims 30 Hippos in Congo’s Virunga National Park

Conservationists Race to Contain Outbreak Threatening One of Africa’s Most Iconic Wildlife Sanctuaries

The silent waters of the Congo’s mighty rivers have become an unexpected battlefield this season, as an insidious outbreak tears through the hippopotamus population of Virunga National Park—one of the most biodiverse and historically significant wildlife reserves on the African continent. According to park officials speaking in recent weeks, at least thirty of these massive semi-aquatic mammals have perished since September, succumbing to what preliminary assessments suggest is a virulent bacterial infection that has wildlife veterinarians and park rangers scrambling to contain its spread. The deaths represent more than just a statistical loss; they signal a potential ecological crisis in a region already burdened by decades of conflict, political instability, and the ever-present threat of poaching.

Virunga National Park, a UNESCO World Heritage Site nestled in the eastern Democratic Republic of Congo, has long been celebrated as a sanctuary for some of the planet’s most endangered species—including the critically endangered mountain gorillas that have made the park famous on the global stage. But the hippopotamus, often overshadowed by their more glamorous primate neighbors, plays an equally vital role in maintaining the delicate balance of the park’s aquatic ecosystems. These colossal creatures, weighing up to three tons and spending most of their lives submerged in the lakes and rivers that crisscross the park’s 7,800 square kilometers of terrain, function as natural engineers of their environment. Their grazing habits keep waterways clear, their dung fertilizes aquatic plant life, and their movements create channels that sustain fish populations and other wildlife. The loss of thirty of these animals in just a few months threatens to unravel a complex web of ecological interdependencies that scientists are only beginning to fully understand.

The disease responsible for this mass mortality event has been identified by park health officials as anthrax—a naturally occurring but potentially devastating bacterial infection that can spread rapidly through herbivore populations when conditions are favorable. Anthrax spores, which can remain dormant in soil for decades, become activated under specific environmental triggers, often following periods of heavy rainfall followed by drought. The spores are ingested by grazing animals, leading to rapid onset of illness and, in many cases, death within days. For hippos, which spend the majority of their time in water and emerge to graze on shoreline vegetation, exposure to contaminated soil or water sources poses an especially grave threat. The disease has been documented in hippo populations before, most notably in Uganda’s Queen Elizabeth National Park in 2004 and again in 2010, where hundreds of hippos succumbed to similar outbreaks. However, the current situation in Virunga carries additional weight given the park’s already precarious conservation status and its long-running struggle against armed groups that have historically used the region as a base of operations.

Park authorities have moved swiftly to address the crisis, implementing surveillance protocols and working with international veterinary experts to monitor the outbreak’s trajectory. Rangers, who already risk their lives daily in the fight against poaching and armed militias operating in the region, have been deployed to track the spread of the disease and to ensure that carcasses are properly disposed of to prevent further contamination. The disposal process is itself a delicate operation—burning or burying infected animals requires careful consideration to avoid inadvertently creating new sources of infection or attracting scavengers that could carry the bacteria to other areas. Meanwhile, samples from deceased hippos have been sent to laboratories for detailed analysis, with researchers hoping to better understand the specific strain involved and whether it poses any threat to other wildlife species in the park, including the mountain gorillas whose numbers have been painstakingly rebuilt through decades of concerted conservation efforts.

The hippopotamus population in Virunga has already endured a harrowing trajectory in recent decades, with numbers plummeting from a historic high of approximately 29,000 in the 1970s to fewer than 1,000 by the mid-2000s—a catastrophic decline driven primarily by poaching for meat and ivory teeth, as well as habitat loss and the collateral damage of civil unrest. In the years since, focused protection efforts have helped the population rebound to an estimated 2,000 to 2,500 individuals, a fragile recovery that conservationists now fear could be imperiled by the current outbreak. The loss of thirty animals may seem modest relative to the park’s total hippo population, but the infection’s persistence over several months suggests it has not yet run its course, and the potential for exponential spread remains a genuine concern. Researchers emphasize that monitoring these deaths and intervening where possible is crucial not only for the hippos themselves but also for the broader ecosystem that depends on their ecological role.

International conservation organizations have expressed solidarity with Virunga’s management team, offering technical assistance and mobilizing resources to support containment efforts. The park, which is managed by the Congolese Institute for Nature Conservation (ICCN) with support from the Virunga Foundation, has called for increased vigilance and has urged local communities to report any sightings of sick or deceased hippos along the park’s waterways. Public health officials have also been engaged in outreach to nearby villages, providing guidance on avoiding contact with potentially contaminated water sources and emphasizing the importance of proper meat handling, as anthrax can be transmitted to humans through contact with infected animals or their products. These community-level interventions are critical, as the park’s boundaries are porous and the livelihoods of millions of people in the surrounding region are intimately tied to the same rivers and lakes that the hippos inhabit.

The unfolding situation in Virunga highlights the broader challenges facing wildlife conservation in the twenty-first century, where disease outbreaks increasingly intersect with habitat fragmentation, climate change, and human-wildlife conflict. As ecosystems become more stressed and species populations become more isolated, their vulnerability to pathogens increases—a trend that researchers say is likely to accelerate in the coming decades. For the hippos of Virunga, the current outbreak is a stark reminder of the fragility of even the most resilient species when faced with compounding threats. Yet, amid the sobering statistics and the uphill battle against disease, there remains reason for measured optimism. The park’s conservation team has navigated extraordinary challenges before, from civil war to kidnapping of staff to the brutal assassination of rangers by armed groups, and has emerged with a track record of dedication that few other protected areas can match. The response to this outbreak, characterized by swift action, scientific rigor, and a commitment to protecting every member of the park’s wildlife community, reflects that same indomitable spirit. The world watches with held breath, hoping that the waters of the Congo will once again provide refuge rather than sorrow.