Week4 : Diagnosis

 

 Monkeypox is a rare but potentially serious viral illness, characterized by a blister-like rash that resembles smallpox. Humans contract monkeypox by having close contact with animals or other people who have the virus.

Most laboratories do not have the reagents to do this testing, so state labs or the CDC will need to process the samples to establish a definitive diagnosis. These tests are based on detecting antigenic structures (usually from skin or pox samples or occasionally serum) specific to either monkeypox virus or immunoglobulin that reacts with the virus.

Monkeypox can only be diagnosed definitively in the laboratory where the infection can be diagnosed by a number of different tests:

·         enzyme-linked immunosorbent assay (ELISA)

·         antigen detection tests

·         polymerase chain reaction (PCR) assay

·         virus isolation by cell culture. 

Monkeypox is most commonly spread through close contact with warm-blooded exotic pets (such as prairie dogs, Gambian giant rats, and rope squirrels) that are ill with the virus.

The period between exposure to the virus and the onset of monkeypox illness can be anywhere from a few days to 21 days. However, most people experience symptom onset about 12 days after exposure to the virus.

Voice of America (VOA)'s health correspondent Linord Moudou talks to an infectious disease epidemiologist who has been conducting research on monkey pox in the Democratic Republic of Congo:

 

The infection can be divided into two periods:

·         the invasion period (0-5 days) characterized by fever, intense headache, lymphadenopathy (swelling of the lymph node), back pain, myalgia (muscle ache) and an intense asthenia (lack of energy);

·         the skin eruption period where the various stages of the eruption appear on the face (in 95% of cases), on the palms of the hands and soles of the feet (75%) and on the body nearly simultaneously. Evolution of the rash from maculopapules (lesions with a flat bases) to vesicles (small fluid-filled blisters), pustules, followed by crusts occurs in approximately 10 days. Three weeks might be necessary before the complete elimination of the crusts.

Some patients develop severe lymphadenopathy (swollen lymph nodes) before the appearance of the rash. The presence of lymphadenopathy can help identify the disease as monkeypox since it is not characteristic of either smallpox or chickenpox. The symptoms of monkeypox usually last from 14 to 21 days.

References:

Hudson, Paul N.; Self, Joshua; Weiss, Sonja; Braden, Zachary; Xiao, Yuhong; Girgis, Natasha M.; Emerson, Ginny; Hughes, Christine; Sammons, Scott A.; Isaacs, Stuart N.; Damon, Inger K.; Olson, Victoria A. (2013): Monkeypox disease progression timeline. Figure_5.tif. PLOS ONE. 10.1371/journal.pone.0035086.g005. 

 Monkeypox. (2011, February 1). Retrieved April 8, 2015, from http://www.who.int/mediacentre/factsheets/fs161/en/

Updated Interim Infection Control and Exposure Management Guidance in the Health-Care and Community Setting for Patients with Possible Monkeypox Virus Infection. (2008, September 5). Retrieved March 31, 2015, from http://www.cdc.gov/ncidod/monkeypox/infectioncontrol.htm