Despite a great increase in our understanding of the molecular biology of the viruses associated with acute upper respiratory tract viral infections (URTIs) there is a remarkable lack of knowledge and ideas about why URTI should exhibit a seasonal incidence. Most publications in this area either acknowledge a complete lack of any explanation for the seasonality of URTI or put forward an explanation relating to an increased "crowding" of susceptible persons in winter. This review will discuss some of the ideas concerning the seasonality of URTI and put forward a new hypothesis for discussion, namely that seasonal exposure to cold air causes an increase in the incidence of URTI due to cooling of the nasal airway. The hypothesis is supported by literature reports demonstrating that inhalation of cold air causes cooling of the nasal epithelium, and that this reduction in nasal temperature is sufficient to inhibit respiratory defences against infection such as mucociliary clearance and the phagocytic activity of leukocytes. A case is also made to suggest that warming of the nasal airway during fever and nasal congestion may help to resolve a current URTI.

/pdf/an-explanation-for-the-seasonality-of-acute-upper-h362iex88h.pdf

An Explanation for the Seasonality of Acute Upper Respiratory Tract Viral Infections

Epidemiology and seasonality of respiratory tract virus infections in the tropics.

Background.Incidence and severity of respiratory infections are increased in day-care center attendees. Streptococcus pneumoniae is an important contributor to these infections.Objective.To examine whether the use of a pneumococcal conjugate vaccine could reduce the occurrence of respiratory infecti

Effect of a conjugate pneumococcal vaccine on the occurrence of respiratory infections and antibiotic use in day-care center attendees.

Human rhinoviruses: the cold wars resume.

CLASSICALLY, one episode of respiratory infection is considered to be produced by one etiologic agent1 2 3 4 5; occasionally, however, multiple infectious agents have been recovered from patients with respiratory illness, suggesting a more complicated pathogenesis.6 7 8 9 10 The frequent occurrence of staphylococcal pneumonia during epidemic influenza has been reported on several occasions,11 , 12 and in some cases, apparent synergism between viruses and bacteria has been noted.13 14 15 16 17 18 19 20 21 MacLeod18 has called attention to the importance of a previous viral infection in the pathogenesis of pneumococcal illness. Recent studies observed significant growth of pathogenic bacteria in throat cultures from patients with rhinovirus infections.6 The present report compares . . .

Bacterial-viral interrelations in respiratory infections of children.

Studies in the Virgin Islands, Labrador, and Alabama, suggest that colds are incited by some specific agent with which we are not yet familiar. They suggest also that the secondary and more severe symptoms associated with colds may be due to certain aerobic flora commonly found in the nasopharynx. Types of pneumococci which are virulent (to white mice) and true Pfeiffer's bacilli requiring both V and X substance (and forming indol?) seem to be of particular importance in these secondary infections. The studies indicate that the specific agent which initiates colds is infectious in nature, and spread by direct contact, with an incubation period of 1 to 3 days. There is strong evidence that environmental factors, particularly reduction in atmospheric temperature, have some influence upon the incidence of colds.

https://rupress.org/jem/article-pdf/53/5/733/1179339/733.pdf

A bacteriological study of "colds" on an isolated tropical island (st. john, united states virgin islands, west indies.

Studies of the bacterial flora of the nasopharynx were made in isolated communities in South Alabama and Labrador. The basic flora was determined in both communities. In Alabama an epidemic of common colds was studied. In Labrador cases of sporadic colds and an epidemic of tracheitis were studied. Gram-negative cocci were found in nearly all normal individuals in moderate numbers. In pathological states there was a suppression of these organisms. Staphylococci were found in small numbers in about half of the normal individuals. In pathological conditions they disappeared from most of those affected but were found in increased numbers in a few individuals. Pfeiffer bacilli were absent or present only in small numbers in normal individuals. During the epidemic of colds in Alabama there was an increase in the number of strains recovered and an increase in the relative numbers of the bacilli in each throat. The highest prevalence was found one month after the epidemic had reached its height. In Labrador a similar increase was coincident with an epidemic of tracheitis. During normal periods the majority of the Pfeiffer strains were of the para non-indol-forming type. During epidemic periods the strains recovered were largely true indol-forming B. Pfeifferi. Hemolytic streptococci were rarely found in normals. During disease prevalence periods they appeared in a small number of persons. In Alabama, indifferent streptococci resembled the hemolytic streptococci in their distribution. In Labrador they were found to be widely distributed in both health and disease and composed apparently a part of the normal flora. Green streptococci were found to be widely distributed in fairly large numbers both in health and disease. Intermediates, or organisms midway between green streptococci and pneumococci, were found in moderate numbers in each series of persons studied. Early in the Alabama epidemic they were present in large numbers in nearly all persons. Pneumococci were not found in Alabama in normal individuals. The epidemic of colds in Alabama was accompanied by a marked increase in the incidence of these organisms. In Labrador pneumococci seemed to be part of the normal flora as they were generally distributed throughout the community, in many instances comprising a large proportion of the flora of an individual's throat. The Labrador strains of pneumococci were avirulent. A variety of other organisms such as diphtheroids, Gram-negative rods, and Gram-positive cocci were found in small numbers in many individuals both in health and disease.

https://rupress.org/jem/article-pdf/50/5/643/1140172/643.pdf

Nasopharyngeal flora in health and during respiratory disease in isolated communities in alabama and labrador.

The globoid bodies, identical in morphological and cultural characteristics with the organisms described by Flexner and Noguchi, have been obtained in twenty-two cultures from the tissues of seven monkeys suffering from experimental poliomyelitis. Twenty of the strains were cultivated from the central nervous organs, all being obtained from the cerebrum except one, which was cultivated from the cervical portion of the spinal cord. Two strains were cultivated from the spleen. None of the cultivated strains inoculated produced typical poliomyelitis in monkeys. The recovery of a strain of the globoid bodies from the inoculated monkey is as difficult as is the original cultivation of the organisms from animals inoculated with the ordinary virus of poliomyelitis. Nothing in this study has served to implicate the streptococcus in the pathology of the poliomyelitic process; the streptococcus is, however, encountered as a common contaminant or secondary invader, especially in animals which have been etherized while moribund, or which had died some hours previous to the autopsy. When the infected and paralyzed animals are killed while still strong, secondary invading bacteria, including the streptococcus, tend to be absent from the tissues. A modified, perhaps improved, but alternative method has been devised for the cultivation of the globoid bodies and other microorganisms demanding a high degree of anaerobiosis.

/pdf/cultivation-experiments-on-the-globoid-bodies-of-466e5gi4fd.pdf

Cultivation experiments on the globoid bodies of poliomyelitis.

1. Anaerobic methods have been devised which depend upon the catalytic action of platinized asbestos upon hydrogen and oxygen. 2. The methods may be utilized for the growth of anaerobes in test-tubes, upon Blake bottles, in flasks, and in a large container. 3. Because oxygen is so completely removed, the methods are of great value in the successful cultivation of absolute anaerobes.

/pdf/new-anaerobic-methods-4ljomu2t0u.pdf

New anaerobic methods

1. Pneumococcus Type IV of low virulence was the prevailing organism in fifty-eight cases of pneumonia studied in southern Alabama. Fixed types of pneumococci were not common. 2. Pneumoma was more prevalent in children from 5 to 15 years of age than in adults. As a rule, the disease ran a mild course. 3. Most of the cases of pneumonia gave a definite history of an acute cold antedating the attack of pneumonia by a period of 5 to 8 days. Exposure alone did not seem to predispose to pneumonia, but those with an acute cold who were exposed to chilling of the body surface frequently developed pneumonia. 4. There were seven "family epidemics" of pneumonia. In each instance there was a family epidemic of colds antedating the pneumonia. The pneumococcus was found in large numbers in the nasopharynx of those suffering from colds as well as in the pneumonia patients. 5. The epidemiology of pneumonia in the pioneer days of American history has many points in common with the epidemiology of pneumonia in a rural isolated area in southern Alabama today. This suggests that the crowded conditions and frequent contacts of modern city life have built up a community resistance to avirulent strains of pneumococci.

https://rupress.org/jem/article-pdf/50/2/233/1178608/233.pdf

Wilson G. Smillie

Papers

A bacteriological study of "colds" on an isolated tropical island (st. john, united states virgin islands, west indies.

Nasopharyngeal flora in health and during respiratory disease in isolated communities in alabama and labrador.

Cultivation experiments on the globoid bodies of poliomyelitis.

New anaerobic methods

A study of pneumonia in a rural area in southern alabama.