Chapare haemorrhagic fever

Chapare infection is a type of haemorrhagic fever—other examples of haemorrhagic fevers include dengue fever, Crimean-Congo haemorrhagic fever and Ebola virus disease.

Chapare haemorrhagic fever gets its name from the Chapare region in Bolivia where the first known case of this illness occurred in 2003, resulting in one death. The next outbreak of this disease occurred in 2019 in a different province of Bolivia—Caranavi, over 700 kilometres away by road—which resulted in five cases and three fatalities, including two medical professionals.

Evidence or research on this illness is limited by the very small number of cases on record, but so far the disease has had a high mortality rate.

The Chapare virus can jump from rodents to humans when people come in contact with infected animals through their bite, scratching, urine, saliva or droppings.

Human to human transmission has recently been confirmed by the US CDC—this can happen through contact with the patient’s body fluids such as saliva, urine and semen and during healthcare procedures like chest compressions, cardiopulmonary resuscitation, intubation or any procedure which can cause aerosolization.

Scientists don’t yet know if in utero transmission from expecting mother to child is possible, though there is some evidence that infection during pregnancy could lead to complications like miscarriage or even death of the mother or newborn.

More research is needed to determine the exact animal reservoir and transmission method of the virus, though.

There are fewer than 10 cases of this infection on record as of 17 November 2020. As such, there is limited information available on it. Having said that, we know that the incubation period—the time lag between contracting the infection and showing symptoms—of Arenaviruses can be anywhere from four days to three weeks. Additionally, according to the CDC, confirmed patients of Chapare haemorrhagic fever have reported some or all of these symptoms:

• Fever
• Headache
• Joint pain
• Muscle pain
• Pain behind the eyes
• Stomach pain
• Vomiting
• Diarrhoea
• Bleeding gums
• Skin rash
• Irritability
• Bleeding

Chapare haemorrhagic fever is caused by the Chapare virus of the Arenaviridae family.

We don’t yet know which exact rodent is responsible for spreading Chapare haemorrhagic fever, but given that viruses of the Arenaviridae family typically use rodents as their reservoir animal, reducing exposure to rodents could reduce overall risk.

The at-risk population could be:

• People working in the fields or granaries or godowns where there are lots of rodents. 
• Homes and buildings infested with rats and other rodents may also pose a risk.
• Health care workers, researchers and laboratory staff may also be at risk of infection if they are taking care of patients with this illness or working on this virus.

The good news is that the two known outbreaks of this virus have been limited to Bolivia alone, there is no immediate threat of a wider outbreak and scientists are doing everything they can to discover and neutralise newer viral diseases. The bad news is that rodents can travel easily and it may be irresponsible to ignore the risk of transmission to other places in a globalised world.

It is important to maintain cleanliness and control rodent populations in and around your home and workplace.

You should also avoid places that could be infested with rodents. Wash your hands regularly and wipe down food packages before storing them away.

Care should also be taken if you are travelling to or back from an area where this illness is known to occur.

If you are a healthcare worker in an area where Chapare virus infection is seen, make sure to wear personal protective equipment and take all precautions during procedures like intubation.

Recovered patients could shed the virus in their blood, saliva, urine, semen and faeces for a few months after recovering—so they should continue to take all the precaution even after their symptoms pass. They should also avoid having sex until their doctor says it’s okay.

According to the World Health Organization, haemorrhagic fevers typically have a sudden onset and present with symptoms like fever, malaise, headache and muscle pain followed by sore throat, vomiting, diarrhoea, skin rash and bleeding. If you or a loved one develops these symptoms, take proper precautions like wearing face masks and maintaining proper distance. Call the clinic or doctor ahead of your visit.

The doctor will make a diagnosis based on whether there is an outbreak of this virus in your area, your symptoms and tests.

There’s no specific test for Chapare haemorrhagic fever yet. According to the US CDC, the few cases of Chapare illness so far were confirmed via blood tests, molecular assays and real-time reverse transcription-polymerase chain reaction (rRT-PCR).

The doctor may also order these tests to rule out other illness with similar symptoms like the Bolivian hemorrhagic fever (Machupo virus), infection by the South American New World arenaviruses, dengue, leptospirosis, yellow fever and hantavirus infection.

There is no known treatment for this illness yet. Supportive treatments could include:

• Fluid therapy to maintain hydration
• Managing any signs of shock through fluid therapy or using vasopressin
• Sedation
• Pain relief medications
• Blood transfusion, if necessary