The recovery of smallpox virus from patients and their environment in a smallpox hospital

Attempts had been made in 1961 to recover smallpox virus by air sampling in smallpox wards and close to the mouths of smallpox patients, but these had been largely unsuccessful, possibly owing to the air sampling method used. Further attempts were therefore made in 1963, with a fluid impinger for air sampling and with Petri dishes placed below the orifice of the impinger to collect large droplets or particulate matter that the impinger might miss.Air samples from near the patients' mouths yielded little virus, this being more readily recovered from the settling-plates. Patients' bedclothes sampled with the impinger yielded rather more virus, but again even more was obtained from the Petri dishes.The results suggest that contamination of the air in the vicinity of smallpox patients is due to relatively large particles of infected dust from the patients' bedclothes rather than from fine droplets or droplet nuclei coming from the upper respiratory tract. Secretions from the mouth and upper respiratory tract appear to be responsible for the early contamination of pillows and bedclothes.

Haemorrhagic smallpox. I. Preliminary haematological studies

In an investigation of specific haematological defects that might account for the haemorrhagic diathesis in certain smallpox patients, 93 patients with haemorrhagic and non-haemorrhagic forms of the disease were subjected to a variety of bleeding and coagulation studies. The findings indicate that smallpox patients with no clinical evidence of haemorrhage have no significant clotting defects although many have decreased platelets and clot retraction abnormality. Patients with the late haemorrhagic form of smallpox consistently show thrombocytopenia and associated abnormalities in the bleeding time, tourniquet test and clot retraction; some also have slightly depressed specific prothrombin activity.Patients with the severe, and uniformly fatal, early haemorrhagic form have severe thrombocytopenia, a marked decrease in specific prothrombin activity and prolongation of the prothrombin complex times. They also have a marked prolongation of the thrombin time, suggesting the presence of a circulating antithrombin.Both early and late haemorrhagic smallpox patients also have a marked abnormality of prothrombin consumption, indicating impaired plasma thromboplastin production. This finding could be explained by the thrombocytopenia present in all haemorrhagic cases.

Haemorrhagic smallpox. 2. Specific bleeding and coagulation studies

A total of 60 patients in Madras with haemorrhagic and non-haemorrhagic clinical forms of smallpox were investigated by a variety of bleeding and coagulation studies in an attempt to reveal specific haematological defects that might account for the haemorrhagic diathesis in certain cases of smallpox.The non-haemorrhagic smallpox patients had no coagulation abnormalities, although some had thrombocytopenia.The early haemorrhagic patients showed a deficiency of platelets, prothrombin and accelerator globulin, and increased circulating antithrombin. Patients with the late form of haemorrhagic smallpox showed significant thrombocytopenia and less severe deficiencies of the same coagulation factors; a few also had increased antithrombin.The authors suggest that therapy with fresh, frozen or lyophilized plasma should be tried; fresh, platelet-rich plasma should offer the greatest benefit.

Smallpox frequency and severity in relation to A, B and O blood groups

The results of routine determination of the blood group of smallpox patients admitted to a Madras hospital over a six-month period suggest that the distribution of blood groups among such patients and the severity of illness among patients of various blood groups do not support the hypothesis that susceptibility or resistance to this disease is associated in any direct way with the possession of A or B blood group substances or antibodies to them. The results reported and other considerations discussed make it improbable that the distribution of blood groups among the population of South India has been influenced by the endemic prevalence of smallpox in that part of the world.