Spatial distribution and seroprevalence of Newcastle disease (ND) in Kaduna State, Nigeria

Abstract

Background: On 5th December 2018, the Field Epidemiology Training Program (FETP) was notified of a varicella outbreak in a female psychiatric ward in the Eradah Complex for Mental Health in Riyadh. We conducted this outbreak investigation to describe the causative organism, its source, its mode of transmission, and identify challenges in case management and outbreak control in this unique healthcare setting.Methods and materials: An observational descriptive case series study was conducted. We defined the suspected case of varicella as a patient with sudden onset of disease with mild fever, generalized maculopapulovesicular rash with no apparent cause, to be confirmed by the laboratory or epidemiological link. We reviewed patients' records, and the relevant data set was retrieved (demographics, symptoms, and vaccination status). We interviewed staff patients, but unfortunately, psychiatric admitted patients could not be interviewed because they are unstable. Meetings with the varicella outbreak team, public health officials, and medical managers were held.Results: We identified a total of 9 confirmed cases of varicella (5 admitted patients, 4 staff) out of 78 females (ward 14B) and one suspected case. The mean age of cases was 35.5 years (range = 25-48 years), 55.5% of cases were Saudi. All cases were epidemiologically linked: The incubation period ranged from 8-17 days (average of 14 days). 100% had a maculopapular rash, 77.8% had vesicles, and 55.6% had a fever. The index case of this outbreak was most likely a nurse who diagnosed to have chickenpox on 17 September. The secondary attack rate was 10%. 22% reported previous varicella vaccination. All cases recovered without any complications. Conclusion:Based on symptoms, incubation period, the epidemiological investigation, we found evidence of probable nosocomial transmission of varicella virus from person-to-person between the staff and the patients due to close contact. We recommended screening of exposed patients and staff, vaccination of those who have negative varicella serology, affording isolation rooms for females' wards and continuous follow-up until no new case appears for 42 days (2 incubation periods) after the rash onset of the last identified case to ensure that the outbreak has ended.