Saturday, November 3

Still here! - but except for a certain concern over the troubles which have beset us, it has been a thoroughly enjoyable time. I am a little embarrassed that we are still guests of the Navy, but the officers are such generous chaps that they will not think of our going over to a hotel, and indeed it is the privilege of their company which has made it so pleasant to be here. Generally we dine with the men, and often go to a movie in the evening. We have seen "Treasure Island", "Murder at the Vanities", and tonight saw an atrocious flicker called "Dames" which made us curl up in our boots in shame for our otherwise quite capable Hollywood.

Nice Henry Born has not deserted us a moment, and has done a succession of kindnesses which go measures beyond mere "service", of which the Shell Company is very proud. We have lunched together, driven about town, and once paid a visit to the Juhu Airport where the Bombay Flying Club has a hangar. Born is a member of the Club and has about 30 hours flying although he was not one of those who made the long flight to England and return, which recently has been completed. It was this group that got lost in the desert in Mesopotamia. The four pilots were all Indians, with only 30 to 150 hours experience apiece, but they had an instructor along.

Bombay is so hot and humid that it takes the life right out of you; energy and ambition simply disappear, and I do not understand how these fellows can take it so easily. It has been raining very hard for three days, and the storm warning signals have not given us much peace of mind, for an intense cyclone has been expected momentarily. The wind has been strong and it has been almost impossible to go aboard the airplane, because it is constantly pitching and tossing so that its floats are under water most of the time. We have put on extra ropes and have brought ashore all of the valuable equipment in case she founders.

The Menace of the Airplane in India: YELLOW FEVER. Yesterday morning a long editorial appeared in the Times of India, which began:

"By aeroplane, motor car and train India is being brought rapidly closer to the rest of the world - its progress and its diseases . . . . Rapid travel has increased the risk of yellow fever spreading around the tropics and this is now so keenly realized in Bombay City that from August 1933, to March last, Dr. R. K. Mhatre, Officer-in-charge, Malaria Branch, Public Health Department of Bombay Municipality, undertook a survey of the Aedes mosquitoes, in Bombay, these mosquitoes being the usual vehicle for the yellow fever virus. In his report Dr. Mhatre justifies the worst fears of those who have believed that should yellow fever cross Africa from west to east, India would find herself in a very dangerous position . . . It has been proved that the common Aedes aegypti mosquito of India can transmit the disease and that the common Indian monkey is susceptible to it. There is thus in India a non-immune population living in intimate contact with an efficient insect carrier and an abundance of susceptible animals, capable of acting as a reservoir for the virus, together with a climate suitable for the transmission of the disease."

"Dr. Mhatre goes very carefully into the problem of controlling the mosquito. He points out that while many mosquito breeding places have been removed, there are still many where the Aedes can breed almost with impunity. In spite of the inconvenience which may be considered, Dr. Mhatre holds the view that nothing short of the complete removal of roof gutters will solve the problem of mosquito control."

This passage bears unusual significance, coming as it does on the heels of the Melbourne Race. It is extremely probable that if the air race had commenced in Sierra Leone or the Gold Coast of western Africa, instead of in England, Yellow fever would have been introduced for the first time into India. This threatening statement seems absurd when one considers that the disease been endemic for at least four centuries in western Africa and in the Caribbean Sea, yet never has it been transported to India's fertile household. In explanation it should be added that yellow fever is rarely found beyond the area bounded by the tropics of Cancer and Capricorn, and that the usual ocean trade routes require a voyage of long duration over a route which extends outside of these latitudes, and this is probably sufficient protection of itself to prevent transportation of the disease.

India's problem is to prevent admission to the country of the yellow fever virus, and this hinges on the life cycle of the virus. The germ has only two hosts, mammal (primate) and mosquito. The human being who has been bitten by an infected mosquito becomes almost immediately a carrier of the virus, although the symptoms of illness appear only after 3 to 6 days. From the 6th to the 9th days (the first 3 days of active illness) he is still a carrier and can pass the virus on to any Aedes mosquito which may bite him. If he survives the fever for a longer period, the blood becomes non-infective and he is free from danger to the rest of the community. Granting, therefore, that the disease can be recognized soon after the appearance of symptoms, the transportation of yellow fever by man requires that the journey from an endemic center to a susceptible region be accomplished within six or seven days after the mosquito bite occurs.

The mosquito plays a role almost the opposite to that of the human being in carrying the virus. Dr. Mhatre points out that the life of the female mosquito is directly dependent upon an uninterrupted supply of animal blood, whereas the male mosquito is not a "biter." The female therefore, is responsible for the woe of yellow fever. During the first 12 days after she sucks blood from a feverish patient, she is not dangerous, but from that time on is unwittingly a carrier of the disease, and her every "bite" into mammalian skin leaves behind a generous supply of the virus in the blood of the animal bitten. The disease is not hereditary among mosquitoes, but having once acquired it they remain carriers throughout their stormy existence, which may last from three to six months. The questions of transportation of infected female mosquitoes from endemic centers to new susceptible areas is therefore of vital importance, and it is significant that they seldom survive a period of starvation for more than 48 hours. Transportation of the yellow fever virus by mosquitoes requires, therefore, that the insects move in company with animals, or that the journey from an endemic center to a susceptible region be accomplished in less than two days. (Later on in Calcutta I asked Lieutenant-Colonel Knowles how long female Anopheles and Aedes mosquitoes can live without animal blood. He answered that Anopheles ordinarily feeds on blood only at long intervals, and may survive as much as 50 days on carbohydrate solutions without blood. He knew of no data on the Aedes mosquito, but thought that it would react in a similar fashion. If this is true, India's situation is even more precarious than Mhatre pointed out.)

Delays in transportation have protected India thus far from the scourge of what would constitute the most dreadful disease ever to visit her territory, and it would undoubtedly be a blessing to the country if aerial traffic were prevented between the areas where yellow fever is endemic and these susceptible regions.