Old Pathogen Returns to Plague a Modern World
Cholera is rapidly spreading in Mozambique, with over 1,200 people infected. Since the outset of 2017, cholera has spread from the capital city of Maputo (pictured above) to three of its ten provinces. Health officials report other areas in the country are seeing case counts rise, and two deaths have been logged so far.
In modern times, cholera is believed responsible for a wave of seven pandemics that have killed millions of people in India, Europe, North America, Asia, Africa, Indonesia, and beyond.
Causing intense intestinal infection, the rod-shaped bacterium Vibrio cholerae causes severe diarrhea, vomiting, cramps, and acute loss of body fluids. Without treatment, death can occur within hours. While cholera is rare in the US, approximately 3.5 million cases occur worldwide, with more than 100,000 deaths per year. The disease is called "the blue death" for the pallor that descends on a human body devoid of fluid.
Usually ingested in contaminated water or food, the bacteria takes up residence in the small intestine for up to three days before symptoms arise. When the severe form of the infection takes hold, victims lose up to a liter of water per hour, through vomiting and diarrhea, and eventually suffer circulatory collapse and death. Approximately 10% to 15% of victims suffer the acute form of the disease.
The intense diarrhea and vomiting present during a cholera infection is an attempt by the body to flush away the vibrio pathogen. In vomit and excreta, vibrio get a free ride out of the body. Because cholera is usually associated with poor sanitation and fecal contamination of water supplies, new victims are as close as the next unwashed hand or contaminated stream.
The majority of people who live in Mozambique live in rural settings. The country has suffered successive cholera outbreaks since 1973, when the bacterium was first identified there. Poor sanitary conditions, lack of infrastructure, flooding, and overcrowding are just a few of the factors that perpetuate cholera epidemics that occur primarily during the rainy season from December until June.
Preceded by a year of drought, the current epidemic was driven by heavy rains that spread V. cholerae throughout the country. In February, flooding from a tropical storm killed at least seven people.
During a cholera infection, V. cholerae does not permanently damage its host. The extreme danger of the disease is dehydration that occurs so quickly that the body fails. With the right supportive treatment, patients close to death can shakily walk out of a treatment center within two days.
An article in the New York Times describes a treatment center in Dhaka, Bangladesh, that is set up solely to triage and treat victims of diarrheal disease. The hospital treats more than 200,000 patients a year with a simple protocol that includes beds covered with plastic sheeting, a hole in the bed for diarrhea to drain, and a bedside catch basin to contain vomit. Each bed has an IV pole and patients receive electrolytes. When able to swallow, patients sip rehydration drinks and are given antibiotics. The center saves hundreds of lives per day.
With proper water treatment, V. cholerae is safely contained in wastewater if it is not the drinking supply for the next town downstream. Despite that, urban planning and adequate wastewater treatment facilities are just not a reality in many parts of the world. Oral vaccines that offer limited immunity are available for severely impacted regions.
Like all vaccine campaigns, the most effective oral cholera vaccine campaigns work best when planned proactively, rather than during crises. The cholera vaccines given to native populations are different than those approved for travelers from the US. In either case, the vaccines are not known to confer lifelong immunity. Because of that, overall public health infrastructure and education are essential aspects of cholera prevention, wherever in the world it occurs.
This is the third year in a row that Mozambique has suffered a cholera outbreak. In 2015, 41 people in Mozambique died from this preventable, treatable infection. Where available, basic treatment and standard water treatment facilities can stop this pathogen that has caused humans centuries of death and suffering.