1955 Durban outbreak

In February, 1955, near the end of summer, a disease resembling poliomyelitis struck the nursing staff of Addington Hospital in Durban, South Africa. A total of 98 nurses became ill.

Addington Hospital at the time served the European and "Coloured" populations of Durban, but not Asians or Africans.

Onset
Patients typical presented with severe headache 14 days after onset.

Symptoms

 * respiratory-tract infection or flu-like illness
 * severe headache
 * extreme lassitude
 * stiffness of the neck, backache
 * muscle pain and cramps
 * muscle weakness
 * paresthesia
 * temporary paralysis worsened by exertion
 * sweating of the extremities

"In certain cases symptoms and signs were very slight, and recovery was rapid; in others the illness proved extremely debilitating and protracted, with residual signs or relapses three years after the onset."

Signs & findings

 * low-grade fever or absence of fever
 * tachycardia
 * neck stiffness
 * reversal of normal sleeping pattern
 * slight facial muscle weakness, diminution of facial sensation
 * difficulty initiating movement
 * reflexes variable (some abnormal)
 * patchy areas of diminished sensation

"Since exercise definitely aggravated weakness and pain, physiotherapy in the initial stages was contraindicated."

Epidemiology
The absence of spread to other hospital personnel or patients initially led physicians to suspect a toxic substance common to the nurses' quarters might be the cause. However, the disease eventually spread to nurses who were not living in the hospital, and sporadic cases were later admitted from the city, all supporting a theory of infection.

After a field investigation, it was suspected that the hospital outbreak was an episode in an infection which has been occurring in the general population for some weeks and months, but went unrecognized until it "broke out with explosive force among the nurses."

Among the 98 cases within the hospital, the ages of those affected ranged from 17 to 49, although the majority of cases were 25 years of age or younger. While several nurses became ill while working in the children's ward, none of the children themselves became ill, suggesting that while children could be carriers, they were themselves immune: "...unlike poliomyelitis, the changes at puberty render the individual susceptible, since cases occurred in adolescents and the incidence among teenagers was high." In the 30 cases outside the hospital, the age range was 15 to 54.

Prognosis
More than 11% of the patients were still severely disabled after three years (a greater proportion may have had more mild impairments, but this was not reported).

The study authors noted, "In the acute phase complete bed rest is essential, since any form of activity tends to evoke painful cramps in the affected muscle-groups. Moreover, in our most serious relapse cases, most of the nurses admit to having been active during the acute phase."