Broad characterizations of a disease's virulence or pathogenicity in the population can be misleading, since populations don't get illnesses, individuals do. And each individual comes with their own set of circumstances; age, comorbidities, lifestyle, previous exposures, etc.
Only a few short months ago the Zika virus was considered so mild, so inconsequential, that few had bothered to study it. Whether Zika has recently changed, or we're just now noticing its impact, today everybody is studying it.
Another arbovirus - originally described as relatively mild (at least compared to Dengue) - is Chikungunya fever (CHIKF). The mantra has been, CHIKF will make you miserable for a few weeks, maybe even leave you with prolonged or permanent disability, but it is not likely to kill you.
And for 99% of those infected, that appears to be true.
But with Chikungunya's arrival in the Americas two years ago, and its subsequent epidemic spread throughout Latin America, more cases are being observed and documented than ever before.
And over the years we've seen some rare and unusual complications, including Optic Neuritis, and Guillain-Barré Syndrome.
About a year ago, In Chikungunya fever: Atypical and lethal cases in the Western hemisphere: A Venezuelan experience doctors described sepsis, respiratory failure, and unusual skin necrosis among severely ill CHIKF patients (see also Nasal Skin Necrosis: An Unexpected New Finding in Severe Chikungunya Fever).
Today the EID Journal carries a dispatch that describes a small number (n=450) of hospitalized CHIKF cases on the Island of Guadeloupe during an epidemic that affected ≈160,000 residents.
Among those 450 sick enough to be hospitalized, 42 had severe disease. Of those, 25 has sepsis or septic shock, and 12 died.
Severe Sepsis and Septic Shock Associated with Chikungunya Virus Infection, Guadeloupe, 2014
Amélie Rollé, Kinda Schepers, Sylvie Cassadou, Elodie Curlier, Benjamin Madeux, Cécile Hermann-Storck, Isabelle Fabre, Isabelle Lamaury, Benoit Tressières, Guillaume Thiery, and Bruno Hoen
In November 2013, the first autochthonous cases of chikungunya virus (CHIKV) infection were identified in the territory of Saint-Martin in the French West Indies (1).
AbstractDuring a 2014 outbreak, 450 patients with confirmed chikungunya virus infection were admitted to the University Hospital of Pointe-à-Pitre, Guadeloupe. Of these, 110 were nonpregnant adults; 42 had severe disease, and of those, 25 had severe sepsis or septic shock and 12 died. Severe sepsis may be a rare complication of chikungunya virus infection.
Since that time, local transmission of the virus has been identified in nearly all Caribbean islands and in Central and South America (2). In Guadeloupe, an outbreak started in the first weeks of 2014 and ended by November 2014. No new definite case of chikungunya has been reported since January 2015. During the 2014 outbreak, ≈40% of the population (≈160,000 persons) became infected with CHIKV.
However, the hospitalization rate for chikungunya was less than 0.5%. A total of 450 patients with CHIKV infection and a positive reverse transcription PCR (RT-PCR) test result for CHIKV were admitted to the University Hospital of Pointe-à-Pitre (UHPAP), Guadeloupe, and were hospitalized >24 hours. Of these 450 patients, 241 were children, 99 were pregnant women, and 110 were nonpregnant adults. The objectives of our study were 1) to describe the characteristics of nonpregnant adult patients who had atypical or severe forms of the disease and 2) to search for predictive factors for severe forms.
Although chikungunya usually has a mild course, severe life-threatening complications can develop during the acute phase of the disease (6,7). Previous studies indicate that the disease can be complicated by severe multiple organ failure and lead to death (8,9). Very recently, the first cases of severe sepsis and septic shock that could be attributed to CHIKV infection were reported (10,11). In some of these cases, acral skin necrosis was observed (11).
The replication of viruses, especially of the family Herpetoviridae, has been shown to occur frequently during the course of septic shock syndromes of bacterial origin, not only as a stress-induced reactivation but also as a superinfection causing additional morbidity (12). By contrast, cases of virus-triggered septic shock have been reported only rarely (13), although a recent cross-sectional study of septic shock syndromes in a pediatric population suggested that viruses might be the only etiology in up to 10% of cases (14). On the other hand, genuine acute severe viral infections might be complicated with a bacterial septic shock, which is well known to occur in cases of influenza but has also been reported in cases of arboviral diseases, such as dengue fever (15).
In our study, none of the 25 patients who had a positive CHIKV RT-PCR test result and a severe sepsis or septic shock syndrome early in the course of chikungunya had another organism identified as a potential cause of sepsis. This finding strongly suggests that CHIKV can, in rare cases, cause severe sepsis and septic shock syndromes, an observation that had not been reported until very recently. Additional studies are needed to identify any background characteristics that might be associated with the onset of severe sepsis or septic shock.
Dr. Rolle is a resident in the Anesthesiology and Intensive Care Departments at the University Medical Center of Pointe-à-Pitre, Guadeloupe, French West Indies. Her research interests include severe forms of tropical diseases that require intensive care and sickle-cell disease.