Recent Chikungunya Virus Infection in 2 Travelers Returning from Mogadishu, Somalia, to Italy, 2016

2 positions owing to mixed bases. The chromatogram showed equal intensities at both positions C and T (Figure, http://wwwnc.cdc.gov/EID/article/22/11/16-1171-F1. htm). This finding indicates that quasispecies might be present. These positions in the human sequence coincided perfectly with 2 of the 3 positions found to vary in the sequence obtained from oyster sample D. All 3 base variations were a replacement of a C with a T (Figure), which further supports the presence of quasispecies. However, in this setup, it was not possible to prove the origin of these closely related species. Whole-genome sequencing using next-generation sequencing would be a way to prove the simultaneous presence of all quasispecies in relevant samples. Since the emerging of GII.P17-GII.17 in Asia, sporadic cases have been reported worldwide (3,9). In this study, we established a direct molecular link between a common food source and a series of acute gastroenteritis outbreaks. Even though these represent European outbreaks, our results show that oysters act as vehicles for the rapid spread of emerging noroviruses to distant geographic areas. Furthermore, we document that quasispecies of GII.P17-GII.17 might occur simultaneously in a host. This finding should be considered in future molecularepidemiologic outbreak investigations.

To the Editor: Since chikungunya virus (CHIKV) was first isolated in 1952 (in Tanzania), outbreaks have occurred every 7-20 years in countries in Africa and Asia, and since 2013, it has been identified in the Americas (1,2). However, no cases have been reported from the Horn of Africa (3,4). We confirmed CHIKV infection acquired in 2016 by 2 travelers to Somalia who returned to Italy.
In June 2016, a Somali woman (patient 1) was referred to the Infectious and Tropical Diseases Unit, Careggi University Hospital, in Florence, Italy, because of severe diffuse bilateral arthralgia and edema in hands, wrists, ankles, and feet. Five days earlier, she had returned to Italy from Mogadishu, Somalia, where she had spent 45 days visiting relatives. The woman had been living in Italy since the 1990s and returned to Somalia each year for ≈2 months; she denied travel to other countries. She reported that symptoms started abruptly in May, 17 days after arriving in Somalia (28 days before returning to Italy). At symptom onset, arthralgia was associated with fever and skin rash, which lasted a few days.
In early July 2016, another Somali woman (patient 2) with bilateral arthralgia in her hands, wrists, ankles, and feet associated with foot edema sought medical care at the same hospital 7 days after returning from a 65-day trip to Mogadishu, where she visited relatives. The woman had been living in Italy ≈20 years; the only other travel she reported was to Kenya in 2012. Her symptoms started in June, 20 days after arriving in Somalia (45 days before returning to Italy). At symptom onset, she also had skin rash and fever, which lasted a few days.
Both patients reported that, during the same period, some of their relatives in Mogadishu had similar symptoms and were clinically diagnosed as having chikungunya fever by local doctors. Both also reported that, during the same period, other cases had been reported in Mogadishu by mass and social media and, thus, the local population was aware of the disease.
Serum samples for patients 1 and 2 were positive for CHIKV antibodies (Table). Both patients were treated with nonsteroidal antiinflammatory drugs and corticosteroids and are receiving follow-up.
According to the US Centers for Disease Control and Prevention, as of April 22, 2016, CHIKV had not been reported from Somalia (4), and no evidence exists for CHIKV circulation in that area of the Horn of Africa (3). In addition, on August 3, 2016, we performed a literature search in PubMed, Embase, and ProMED-mail, and found no reports of CHIKV in Somalia. Poorly documented preliminary data on the presence of CHIKV in Somalia were recently reported in 2 documents by the United Nations Office for the Coordination of Humanitarian Affairs. One  1997-1998 and 2006-2007 (6,7), and a dengue outbreak occurred during 1992-1993 (8).
The current outbreak in Somalia could have been triggered by several factors, including circulation of CHIKV in neighboring Kenya (references 8,9 in online Technical Appendix) and heavy rains that led to flooding in southern and central Somalia beginning in January 2016 (reference 1 in online Technical Appendix). CHIKV has the potential to provoke explosive outbreaks in naive populations (9), so the current outbreak may greatly affect the economy and public health in Somalia.
Systematic studies to understand the magnitude of the ongoing epidemic are needed. In the meantime, local public health stakeholders in Somalia and healthcare workers worldwide caring for travelers returning from Somalia should be aware that CHIKV is circulating in the country. This report confirms the importance of travel medicine services in performing early diagnosis of imported arboviral diseases, not only to thwart secondary transmission during periods of competent vector activity but also to help to detect or confirm virus circulation in previously unaffected countries.