TODAY'S BIG THREAT
SEP 8, 2016
A 62-year-old man recently died in Madrid of Crimean-Congo Hemorrhagic Fever (CCHF), infecting an ICU nurse in the process and exposing many other health care workers to the dangerous virus. Two people are isolated and 200 are under observation. The death rate from infection is up to 40%, per WHO.
We are likely to see many more similar outbreaks in the near future, due to climate change and environmental destruction, as I’ll explain below.
Although seen most commonly in North Africa and Asia, the host hard tick, Hyalomma marginatum, and CCHF disease are endemic in southern and Eastern Europe as well. This is the first locally acquired case in Western Europe, reportedly followed a tick bite while the man was walking in the countryside outside the town of Ávila, in the Castilla-Léon region of Spain.
Distribution of Crimean–Congo hemorrhagic fever – CDC
More commonly, the infection is transmitted to herders or slaughterhouse workers, passed through bites from tick-infested cattle or by contact with inflected blood or tissue. Risk is high now in Pakistan, where 150,000 large and 70,000 small animals (sheep, goats) are transported through the country to a large market, to be sacrificed to celebrate the Muslim festival of Eid al-adha next week. CCHF has already killed at least 20 in Pakistan this year. Workers need to protect themselves both from ticks and from blood and body fluids from the infected animals.
Other hemorrhagic fevers
CCHF and Rift Valley fever are caused by a virus in the Bunyaviridae family, rather than a Filovirus, which causes Ebola and Marburg hemorrhagic fevers. Ebola can be transmitted by contact with or eating infected fruit bats, as well as the devastating person-to-person spread via infected blood or body fluids. They are not transmitted via air. In contrast, Lassa fever, from an Arenavirus, is transmitted from eating multimammate rats, or from aerosolization of infected rat feces or urine. Hantavirus, also rodent transmitted, is the most common hemorrhagic fever virus found in the U.S.
The more familiar dengue and yellow fever belong to the Flaviviridae family, are transmitted by mosquito bites, and are a growing threat in the Americas.
Illness, treatment and prevention
Initial symptoms of CCHF are non-specific, including fever, aching and headache, nausea, vomiting and diarrhea; more severe cases can progress to liver and kidney damage, and bleeding.
Tick-borne infections are widespread throughout Europe.
As with preventing Lyme and rickettsial (spotted fever) infections, use of protective clothing and insect repellents is critical.
Interestingly, one Pakistani report chides animal owners for not vaccinating their herds, but WHO indicates there is no approved vaccine for animals or people. Animals can be infective for about 14 days after being bitten by an infected tick, although remaining asymptomatic, increasing the likelihood of workers not using adequate protective efforts.
Use of Ribavirin for CCHF is mixed, with some reports suggesting benefit, and others not. Treatment is primarily supportive.
Climate change and environmental destruction
Predictions are for increasing spread of tick-borne diseases like CCHF throughout Europe. The increase is likely for several reasons. First, the ticks are common parasites on passerine (perching) birds, which include finches, sparrows and song birds, and are brought to Europe by migrating birds.
Importing livestock is a risk, since animals are commonly found to have up to 100 Hyalommaticks on them. Livestock are rarely examined or treated for tick control.
Most notably, degradation of agricultural land has been found to be a risk for increasing theHyalomma tick populations. Also, warmer autumns are allowing for spread of the ticks into new areas. Modeling of climate warming suggests that some areas of Italy, the Balkans, southern Russia, among other, might be particularly affected.
This is the same pattern seen in the U.S., with the range of ticks (and mosquitoes) expanding as the climate warms, spreading previously unseen infections to new regions as they go.
Other infections are also expanding, given human activity. For example, Ebola was fueled by deforestation, bringing people in closer contact with displaced jungle animals. Similardeforestation likely spurred the spillover of SARS from bats to civets that were captured and sold in urban markets. Chagas disease and leishmaniasis in Latin America are two more examples where human changes to the environment have opened new exposures to disease.
Health care worker infection
One of the striking things about this case is the reminder that health care workers are at particular risk of inadvertent infection. While this outbreak in Spain is so far limited, many cases are likely in Pakistan and neighboring areas with the upcoming holiday.
As we saw with SARS, and then with Ebola, and MERS, health care workers put their lives on the line. Particularly disturbing is how these people — and even more so, humanitarian volunteers going to staunch epidemics, are being vilified. This is happening now with Scottish nurse Pauline Cafferkey, who has been facing misconduct charges for the past 18 months for allegedly “allowing an incorrect temperature to be recorded.”
In the U.S., we had the malicious abuse that nurse Kaci Hickox faced from politically pandering Governors Chris Christie and Paul LePage, forcing an Ebola quarantine that defied rational public health needs. Then there was Dr. Craig Spencer, who faced similar, but perhaps less vicious scrutiny and criticism. He wrote an impassioned perspective noting, “Instead of being welcomed as respected humanitarians, my U.S. colleagues who have returned home from battling Ebola have been treated as pariahs…We all lose when we allow irrational fear, fueled in part by prime-time ratings and political expediency, to supersede pragmatic public health preparedness.”
The expansion of Congo-Crimean hemorrhagic fever to Western Europe is but the latest example of how climate change and our destruction of the environment put us at risk of emerging infections. For the short term, visitors to endemic areas anywhere should use effective insect repellents, do daily tick checks, and if becoming ill, alert their physician to details of recent travel. In the longer view, this is another warning to step back and try to live more harmoniously with our environment.
Finally, we need to support health care workers and not vilify them, or there will be no one willing to take the risks to stop epidemics from emerging, often fatal infections.