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Home , Arbovirus, Chikungunya, Dengue virus, Rift Valley fever

LETTERS

Rift Valley among French Troops in Chad To the Editor: During the rainy season every year, outbreaks of self- limiting nonmalarious febrile syn- dromes have occurred in French mili- tary troops on duty in Chad. To deter- mine the cause of these syndromes, the Tropical Medicine Institute of the French Army Medical Corps imple- mented an arbo-virus surveillance program in Marseille. During summer 2001, we collected samples from 50 soldiers who had a febrile illness. All blood spot samples tested negative by enzyme-linked immunosorbent assay (ELISA) for certain (i.e., , , virus, and Wesselsbron virus). However, after co-culture of 31 peripheral blood lymphocyte samples with C6/36 and Vero cell lines collected in NDjamena, Chad, in August to Figure. NSs-based phylogenetic tree of virus strains. Values indicate the bootstrap support of the nodes. Strains isolated in Chad are designated H1CHA01 and September 2001, two strains of Rift H2CHA01, according to the previous abbreviation guidelines (7,8). EMBL accession nos. Valley fever virus (RVFV) were iso- AJ504997 and AJ504998. SNS, Smithburn strain. Branch lengths are proportional to the lated and identified by using indirect number of substitutions per site. immunofluorescence with a specific mouse ascitic fluid and by using in 1967 at the same time as in ed within the East/Central lineage reverse transcriptase-polymerase Cameroon (2); no strain was isolated established previously (6,7), which chain reaction (RT-PCR) and at that time. Since 1977, RVFV infec- contains the virus that circulated in sequencing. In retrospective testing, tion resulted in 600 deaths in Madagascar (1991), (1997– we found that all specimens (3), 300 in Mauritania in 1987 (4), and 1998), and and tested by ELISA for RVFV-specific 200 in Saudi Arabia and Yemen (5,6) (2000–2001) (9,10). Sequencing of immunoglobulin (Ig) M and IgG were in 2000 to 2001. the region in the M and L segments negative. The second serum samples To characterize these RVFV led to the same clustering (not shown), from the two case-patients with these strains, parts of the three seg- suggesting that this virus did not strains, collected 2 months later, were ments (L, M, and S) were amplified evolve by reassortment. Deter-mining strongly positive (IgM 1/200,000; IgG by using RT-PCR and sequenced as the origin of the virus is difficult, but 1/5,000). described (7,8). The figure shows the its genetic properties suggest that this Rift Valley fever, a febrile phylogenic tree constructed from the strain has a Kenyan origin. Before this that affects livestock and humans, is sequence of the region coding for NSs isolation, no RVFV strains from Chad transmitted by mosquitoes and caused in the S segment, by using the neigh- had been genetically characterized. by a virus (genus: , fami- bor-joining method implemented in This strain may be endemic in this ly: Bunyaviridae) that can persist in Clustal W (version 1.6; available region of Central , or the RVFV nature in contaminated eggs. The from: URL: http://www-igbmc.u- strain circulating in the Eastern coun- virus was first isolated in Kenya in strasbg.fr/BioInfo/ClustalW/clustalw. tries may have been transported out- 1930 (1) and is endemic in the region. html). The two strains identified in side of the territory (which was likely In Chad, the disease was first reported Chad are quite similar. They are locat- the case in Yemen and Saudi Arabia in

Emerging Infectious • Vol. 9, No. 6, June 2003 751 LETTERS

2000) (9,10). Of the two case-patients, August–October 2000. Wkly Epidemiol are milder than those caused by C. Rec 2000;75:392–5. diphtheriae. However, some strains of one soldier did not leave NDjamena 6. Arishi H, Ageel A, Abdu Rahman M, Al during his 3-month tour of duty, Hazmi A, Arishi AR, Ayoola B, et al. C. ulcerans produce potent diphtheria whereas the other had been in contact Outbreak of Rift Valley fever, Saudi Arabia, toxin and may cause severe symptoms with livestock in a flooded area before August–November 2000. MMWR Morb similar to those caused by C. diphthe- Mortal Wkly Rep 2000;49:982–5. riae (1). We report a case of a diphthe- onset of symptoms. Contamination 7. Sall AA, de Zanotto PM, Sene OK, Zeller may have occurred through infected HG, Digoutte JP, Thiongane Y, et al. ria-like illness caused by C. ulcerans animals or mosquitoes, although Genetic reassortment of Rift Valley fever infection. sheep living in the area did not show virus in nature. J Virol 1999;73:8196–200. A previously healthy 52-year-old 8. Sall AA, de Zanotto PM, Zeller HG, woman first noticed hoarseness any sign of disease (i.e., spontaneous Digoutte JP, Thiongane Y, Bouloy M. , deaths). The two cases we Variability of the NSs protein among Rift approximately 3 days before admis- describe were self-limiting; however, Valley fever virus isolates. J Gen Virol sion to the hospital. On February 16, deaths from this illness have been 1997;78:2853–8. 2001, severe dyspnea and fever devel- 9. Miller BR, Godsey MS, Crabtree MM, oped, and the patient was referred to reported in nonepidemic settings in Savage HM, Al-Mazrao Y, Al-Jeffri M, et Central African Republic (11). Our al. Isolation and genetic characterization of the emergency room of the Asahi data emphasize that healthcare Rift Valley fever virus from vexans General Hospital by her private prac- providers should systematically con- arabiensis, Kindom of Saudi Arabia. Emerg titioner. Physical examination indicat- Infect Dis 2002;8:1492–4. ed a large stridor, which could be sider Rift Valley fever as a diagnosis 10. Shoemaker T, Boulianne C, Vincent MJ, for febrile syndromes in persons Pezzanile L, Al-Qahtani MM, Al-Mazrou Y, heard without using a stethoscope. returning from Africa, even in nonepi- et al. Genetic analysis of associated Cyanosis was not observed. The demic settings (12). with emergence of Rift Valley fever in endoscopic examination showed a Saudi Arabia and Yemen, 2000–01. Emerg thick white coat covering the Infect Dis 2002;8:1415–20. Jean Paul Durand,* 11. Meunier DMY, Madelon MC, Lesbordes nasopharynx and laryngeal vestibu- Michèle Bouloy,† JL, Georges AJ. La fièvre de la Vallée du lum, and subglottic constriction was Laurent Richecoeur,‡ Rift et les phléboviroses en République also observed. A chest x-ray showed Christophe Nicolas Peyrefitte,* Centrafricaine. Bull Soc Pathol Exot diffuse infiltrates in both lungs. Filiales 1988;81:49–57. and Hugues Tolou* 12. Durand JP, Richecoeur L, Peyrefitte C, Pertinent laboratory findings on *Tropical Medicine Institute of the French Boutin JP, Davoust B, Zeller H, et al. La admission included leukocyte count Army Medical Corps (IMTSSA), Marseille, Fièvre de la Vallée du Rift: spo- of 16.8 x 103/µL and C-reactive pro- France; †Institut Pasteur, Paris, France; radiques de militaires français hors des tein of 20.0 mg/dL. The serum level and ‡3ème Régiment d’Infanterie de zones d’épidémies actuellement connues. Marine (RIMa), Vannes Cedex, France Med Trop (Mars) 2002;62:291–4. of transaminase was normal, and both Wassermann reaction and anti- References Address for correspondence: Jean Paul Durand, HIV tests were negative. Laboratoire Associé au Centre National de Pharyngolaryngitis and pneumonia 1. Daubney R, Hudson JR, Graham PC. Référence des , Unité de Virologie, was diagnosed in the patient. Because Enzootic hepatitis of Rift Valley fever, an undescribed virus disease of sheep, cattle IMTSSA, BP 46, 13998 Marseille Armées, of severe dyspnea, intubation was per- and man from East Africa. Journal of France; fax: 01 40 61 31 51; email: imtssa.vro@ formed, which caused sudden and Pathology and Bacteriology 1931; 34: wanadoo.fr unexpected exacerbation of the condi- 545–79. tion. Severe cyanosis subsequently 2. Maurice Y. Premières constatations sérologiques sur l’incidence de la maladie developed. Extubation was immedi- de Wesselsbron et de la Fièvre de la Vallée ately performed, and a thick white du Rift chez les ovins et les ruminants material was found to be filling the sauvages du Tchad et du Cameroun. Rev lumen of the endotracheal tube. Elev Méd Vét Pays Trop Revue d’Elevage Corynebacterium et de Médecine Vétérinaire des Pays Reintubation was performed, and dys- Tropicaux 1967;20:395–405. ulcerans Diphtheria pnea subsided. The patient was hospi- 3. Meegan JM, Hoogstraal H, Moussa MI. An in Japan talized in the intensive-care unit. epizootic of Rift Valley fever in Egypt in Sulbactam sodium/ampicillin sodium 1977. Vet Rec 1979;105:124–5. To the Editor: Corynebacterium (6 g per day) was intravenously 4. Jouan A, Le Guenno B, Digoutte JP, ulcerans causes a zoonotic infection Philippe B, Riou O, Adam F. An RVF epi- administered for 4 days; however, the demic in southern Mauritania. Ann Inst similar to diphtheria, which is caused symptoms were not much improved. Pasteur Virol 1988;139:307–8. by C. diphtheriae. Studies indicate The symptoms were most consistent 5. Nasher AAW, Shiban AK, Eriyani MA, Aly that of a diphthe- with those of diphtheria. Therefore, Bourgy A, Al Kohlani AH, Benbrake M, et ria-like illness caused by C. ulcerans al. Outbreak of Rift Valley fever, Yemen, the patient was subsequently placed

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