Chikungunya fever

[sharon sanders]

The Lancet 2006; 368:186-187 July 15, 2006
DOI:10.1016/S0140-6736(06)69017-X
Chikungunya fever DT Mourya a and AC Mishra a

See Case Report

In today's Lancet, Patrick Bodenmann and Blaise Genton1 report a traveller who spent time in Mauritius, had several mosquito bites during the trip, and developed chikungunya fever. In southeast Asia, this virus causes large outbreaks and virtually disappears for long periods, probably as asymptomatic cases. The natural cycle of the virus is human-mosquito-human and in west Africa the epizootic cycle involves monkeys.2 Several species of Aedes mosquitoes are associated with chikungunya fever, but A aegypti and A albopictus are the two most important vectors in human beings.2 The manifestations in Bodenmann and Genton's patient are common features of chikungunya fever; the patient developed a rash on the third day, her high temperature subsided 6 days after onset of symptoms, and she had diffuse arthralgia on both hands. Arthralgia can persist for a few days to many weeks.2 Since late 2004, there has been a large outbreak of chikungunya fever in countries near the Indian Ocean.3,4 Diagnosis is usually made by IgM-capture ELISA. However, PCR is useful for diagnosis with acute samples. Treatment is largely symptomatic, as in Bodenmann and Genton's case.
Chikungunya is a self-limiting febrile illness but the current outbreak seems to be more severe than previous outbreaks, because many patients developed complications and deaths have also been reported.3,4 Several European countries have reported cases of chikungunya from travellers who had visited affected countries.3,4 Our experience in an episode of febrile illness at Nagpur in 1965 showed that the disease affected all ages, with a high temperature lasting for 1–7 days, the usual duration being 2–4 days. Some patients developed a morbilliform rash on the second to fifth day of onset.5
Although Bodenmann and Genton's patient did not have haemorrhage, Robinson6 mentioned that some cases at Réunion had mild haemorrhagic signs. Our experience from a small retrospective study in Bangalore showed serum samples that were clinically referred as dengue haemorrhagic fever were negative for dengue, but when further tested, several samples were positive for chikungunya. The laboratory investigations and clinical presentations in some of these cases showed thrombocytopenia and patechial haemorrhage.7 Macular or maculopapular rash, if present, appears most commonly on the trunk, and rarely petechiae are present.8 Severe haemorrhagic symptoms have not been reported in chikungunya cases in Africa; however, they have been reported in some cases during earlier epidemics that in south Asia and southeast Asia.9
The current outbreak can be attributed partly to the absence of herd immunity in the affected population, although in India there was an indication of chikungunya virus activity at a low level.9 Our experience with the current epidemic showed that although all ages were affected, there were more adult cases. During this outbreak, Schuffenecker and colleagues investigated changes in the virus genome leading to its virulence and change in the behaviour and morbidity associated with the disease. They surmised that the outbreak began with a strain related to east African strains of the virus. All the recent Indian Ocean sequences examined shared certain areas, which are different from the previously determined sequences.10
Bodenmann and Genton benefited from rapid development of internet surveillance networks that help the developed world stay informed in real time about epidemics. We believe that this facility is now available in most parts of the world and people, even from rural areas, can obtain health-related information. Nowadays, with telemedicine, experts can be consulted worldwide for specific health-related problems.
Our investigations in India showed that largely rural areas with A aegypti mosquito were affected. The emergence and spread of this virus in densely populated cities and towns can cause high morbidity. The large population is at risk of the illness, especially travellers from regions where this disease is not prevalent.
We declare that we have no conflict of interest.


<!--start simple-tail=-->References

1. Bodenmann P, Genton B. Chikungunya: an epidemic in real time. Lancet 2006; 368: 258. Full Text | PDF (309 KB) | CrossRef
2. Jupp PG, McIntosh BM. Chikungunya virus disease In: , Monath TP, ed. . In: Arbovirus: epidemiology and ecology. vol II:Boca Raton: CRC Press, 1988: 137.
3. WHO. Disease outbreak news: Chikungunya and Dengue in the south west Indian ocean. March 17, 2006:
http://www.who.int/csr/don/2006_03_17/en
(accessed May 1, 2006).
4. Centers for Disease Control and Prevention. Outbreak notice: Chikungunya fever in India. June 19, 2006:
http://www.cdc.gov/travel/other/2006/chikungunya_india....
(accessed May 1, 2006).
5. Rodrigues FM, Patankar MR, Banerjee K, et al. Etiology of the 1965 epidemic of febrile illness in Nagpur city, Maharashtra State, India. Bull World Health Organ 1972; 46: 173-179. MEDLINE
6. Robinson MC. An epidemic of virus disease in Southern Province, Tanganyika Territory, in 1952–53. I: clinical features. Trans R Soc Trop Med Hyg 1955; 49: 28-32. MEDLINE | CrossRef
7. Brighton SW, Prozesky OW, De La Harpe AL. Chikungunya virus infection: a retrospective study of 107 cases. S Afr Med J 1983; 63: 313-315.
8. Mason PJ, Haddow AJ. An epidemic of virus disease in Southern Province, Tanganyika Territory in 1952–53; an additional note on Chikungunya virus isolations and serum antibodies. Trans R Soc Trop Med Hyg 1957; 51: 238-240. MEDLINE | CrossRef
9. Mourya DT, Thakare JP, Gokhale MD, et al. Isolation of Chikungunya from Aedes aegypti mosquitoes collected in town of Yawat, Pune district, Maharashtra State, India. Acta Virologica 2002; 45: 305-309. MEDLINE
10. Schuffenecker I, Iteman I, Michault A, et al. Genome microevolution of Chikungunya viruses causing the Indian Ocean outbreak. PLoS Med 2006; 23: e263.

[sharon sanders]

Case report from above

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&#183;8&#215;109/L; normal range 4–10&#215;109/L) and monocytosis (15%; 2–8%). No other laboratory tests were done other than serology for Chikungunya.

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Figure. Maculopapular rash at presentation


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&#183;42 [positive if >0&#183;15] and IgG negative [positive if >0&#183;10] on Feb 15; IgM 3&#183;51 and IgG 0&#183;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, Robinson3 mentioned fever (100% of the cases diagnosed on La R&#233;union), arthralgia (100%), myalgia (97%), headache (84%), and diffuse maculopapular rash (33%).4 Symptoms appear 4–7 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 time—12% 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 R&#233;union 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.
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Acknowledgments
We thank M Bucher and P Vaucher from the Medical Outpatient Clinic for clinical care and literature search, respectively.
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<!--start tail=-->References

1. Edisan. M&#233;decine 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 1952–53: I clinical features. Trans R Soc Trop Med Hyg 1955; 49: 28-32. MEDLINE | CrossRef
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.
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<!--end tail-->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