EID Weekly Updates:

Emerging and Reemerging Infectious Diseases, Region of the Americas

Vol. 1, No. 9—4 September 2003
Main Updates index

• Outbreak of Plasmodium vivax Malaria in San Juan del Oro, Peru
• West Nile Virus (WNV) in the USA and Canada

Outbreak of Plasmodium vivax Malaria in San Juan del Oro, Peru

According to the Ministry of Health of Peru, since June 2003 there has been an increase in the number of malaria cases produced by Plasmodium vivax in the District of San Juan del Oro (Province of Sandia, Puno), which has been reported by the health authorities as an outbreak. Said outbreak began on 20 June 2003 and has continued to the present time, although there has been a decline in the number of cases over the past few weeks. Up to 23 August, a total of 216 confirmed cases of P. vivax malaria were reported. The outbreak has taken place in a rural setting, mainly affecting male agricultural workers between the ages of 15 and 44. Six (6) localities in the District have been involved: Azaya, Misky Mayo, Pampa Grande, Pauj Playa, San Ignacio-Curva Alegra, Uramba and Victoria. La Pampa Grande is the most affected of these, with an attack rate of 511 per 1000 inhabitants.

The active search initiated to locate cases with the aim of treating them, as well as intense surveillance and vector control were the measures implemented. Despite the downward trend in the number of cases, certain difficulties have been identified in the area of control, such as the scarcity of antimalarial treatments and incomplete coverage with regard to vector elimination. In addition, all the affected localities are located near the border with Bolivia (Cocos and San Fermín), with a significant number of people moving back and forth-thus creating some difficulties for surveillance and control measures.

Source: Ministry of Health, Peru.

West Nile Virus (WNV) in the USA and Canada

USA, 4 September 2003

According to the Centers for Disease Control and Prevention of the United States (CDC), 2,267 human infections and 43 deaths from West Nile Virus (WNV) have been reported to date, an increase of 53% over the last update (28 August 2003). The States most affected continue to be Colorado, with a 48% increase in the number of infections (940) and an 83% increase in the number of deaths (11); Nebraska, with a 71% increase in the number of infections (326) and double the number of deaths (8) as the last update; and South Dakota, with a 21% increase in the number of detected infections (250) and a 50% increase in the number of deaths (3).

To date, clinical information is available on 98% of those infected (2214): of these, 57% (1257) were reported as mildly ill (fever), 33% (723) as seriously ill (meningitis or encephalitis), and 11% (234) with non-specific symptoms. For more information, see the CDC website.

Source: Division of Vector-Borne Infectious Diseases: West Nile Virus, Centers for Diseases Control and Prevention (CDC), USA.

Canada, 3 September 2003

To date, a total of 131 infections from West Nile Virus has been reported. Nineteen (19) human infections has been confirmed, and studies are being continued on the other 112 possible cases. Since the last update (28 August 2003), the total number of reported infections has tripled. The Province most affected continues to be Saskatchewan, with 10 confirmed cases and 59 probable cases, followed by Alberta with 7 confirmed cases and 37 probable cases. At present, there have been no deaths. More information is available on the Health Canada website.

Source: West Nile Virus Surveillance Information, Health Canada.