E-DRUG: Chikungunya fever
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[As we have had an earlier exchange on this disease ( Februare 2006), this
makes a nice follow-up. Copied as fair use]
The Lancet 2006; 368(9351):258 (15 July)
DOI:10.1016/S0140-6736(06)69046-6
Chikungunya: an epidemic in real time
Dr Patrick Bodenmann MD (a) and Blaise Genton MD (b c)
On Feb 15, 2006, a 28-year-old woman attended our clinic because of
fever, headache, and photophobia that had lasted for 3 days and rash of
1 day's duration. 2 days earlier she had returned from a 2-week trip to
Mauritius. She reported many mosquito bites during her trip. On
examination, there was painful inguinal lymphadenopathy and a
maculopapular rash on her trunk (figure), and her thighs; knees, wrists,
and hands were painful. The differential diagnosis included Chikungunya
fever because of the continuing and large epidemic in Mauritius (1), the
compatible chronology, and the typical clinical presentation. Less
likely diagnoses were primary HIV infection, rickettsiosis, malaria, and
dengue, typhoid, or relapsing fever (see www.fevertravel.ch for details
on differential diagnosis) (2). Rapid diagnostic test and microscopy
were negative for malaria. Full blood count showed a low white-cell
count (2·8×109/L; normal range 410×109/L) and monocytosis (15%; 28%).
No other laboratory tests were done other than serology for Chikungunya.
Because of the high probability of Chikungunya, she was given
symptomatic treatment, discharged the same day, and followed up as an
outpatient. Chikungunya fever was later confirmed by serology results
(IgM positive 0·42 [positive if >0·15] and IgG negative [positive if
0·10] on Feb 15; IgM 3·51 and IgG 0·72 on Feb 28). When the patient was
last seen on Feb 22, 2006, fever had subsided but diffuse arthralgia on
both hands persisted.
Chikungunya is transmitted by Aedes aegypti or A albopictus. In his
original report of this arbovirosis, Robinson (3) mentioned fever (100%
of the cases diagnosed on La Réunion), arthralgia (100%), myalgia (97%),
headache (84%), and diffuse maculopapular rash (33%) (4). Symptoms
appear 47 days after the infecting bite and can be associated with
lymphadenopathy, gastrointestinal symptoms, and mild haemorrhagic signs.
In Swahili, Chikungunya means the illness of the bended walker; indeed,
arthralgia is often severe and can persist for a long time12% of
patients have chronic arthralgia 3 years after onset of illness (5).
During the recent epidemic in the Indian Ocean islands, 12 cases of
meningoencephalitis have been confirmed, which could suggest that the
present strain is more virulent than those causing previous epidemics;
six cases were diagnosed in neonates whose mothers had contracted the
virus 48 h before giving birth and six in elderly people. 77 death
certificates issued in the region between Jan 1, 2006, and March 2,
2006, state Chikungunya as the cause of death, but, for most of them,
there was underlying comorbidity (median age 78 years) (4). Thanks to
the rapid development of internet surveillance networks, more developed
countries can be informed in real time about the dynamic of an epidemic
that potentially threatens travellers' health. Chikungunya on La Réunion
is a good example: once the epidemic worsened in January, 2006, reports
rapidly accumulated with detailed description of clinical cases, rate,
and type of complications. However, the local population had to wait for
the first cases in tourists to see the deployment of effective control
measures. As travel-medicine physicians, we were pressurised by the
media and our patients to give informed advice on whether to go or to
cancel a planned journey. After thorough assessment of the documents
available on the internet, we developed recommendations based on the
evidence from several disease-surveillance systems (1,4). We strongly
discouraged pregnant women, families with young children, people older
than 70 years, and those with significant comorbidity from travelling to
the Indian Ocean islands. We informed other patients about the magnitude
of the risk of contracting the disease and let them decide according to
their own judgment. We reinforced the message on protective measures
against mosquito bites. This case emphasises the importance of
disease-surveillance communication networks, which allow the constant
modification of preventive and therapeutic measures.
Acknowledgments
We thank M Bucher and P Vaucher from the Medical Outpatient Clinic for
clinical care and literature search, respectively.
References
1. Edisan. Médecine des voyages http://www.edisan.fr (accessed March 13,
2006).
2. D'Acremont V, Burnand B, Ambresin AE, Genton B. Practice guidelines
for the evaluation of fever in returning travelers and migrants. J
Travel Med 2003; 10 (suppl 2): 525-550.
3. Robinson MC. An epidemic of virus disease in southern province,
Tanganyka Territory, in 195253: I clinical features. Trans Soc Trop
Med Hyg 1955; 49: 28-32.
4. Eurosurveillance. http://www.eurosurveillance.org (accessed March 2,
2006).
5. Brighton SW, Prozesky OW, De La Harpe AL. Chikungunya virus
infection: a retrospective study of 107 cases. S Afr Med J 1982; 63:
313-315.
Affiliations
a. Medical Outpatient Clinic, Department of Community Medicine and
Public Health, University of Lausanne, Rue du Bugnon 44, 1011 Lausanne,
Switzerland
b. Travel Clinic, University of Lausanne, Rue du Bugnon 44,
1011 Lausanne, Switzerland
c. Swiss Tropical Institute, Basel, Switzerland