Mosquito Ills and Cures

As officers, Meriwether Lewis and William Clark were officially responsible for the health of their men, and they had enough knowledge and experience to recognize the more common ailments of that day, including “ague” and “bilious fevers.” The ague was also known as intermittent fever in America, from its alternate attacks of fevers and chills. It had been termed “mal-aria”–literally “bad air”–in Italy, especially around the Pontine Marshes of Rome. The word malaria didn’t enter the English and American medical vocabularies until after 1820.

Even then, no one perceived the right connection between mosquitoes and water, but only the mistaken one between marshes and their odors. As long as one couldn’t smell marsh gas, it didn’t appear to matter how many mosquitoes were in the air. On 3 August 1804, for instance, the captains came to a positive conclusion about the environment of the “Council Bluff” where they had met with the Otoes and Missourias. As Clark observed, even though the mosquitoes were more numerous than he had ever seen them, “perhaps no other Situation is as well Calculated for a Tradeing establishment. The air is pure and helthy So far as we can Judge.”

On 13 November 1803, as he entered the upper middle stretches of the Ohio River, Lewis–possibly recalling his Army days–noted that those afflictions “here commence their baneful oppression and continue through the whole course of the river with increasing violence as you approach it’s mouth.” Indeed, the zone of intermittent fever extended some distance up the lower Missouri, and down the Mississippi to the Gulf.

Four days later he reported a mild attack of the disease himself. He experienced “a violent ague [chill] which continued about four hours and as is usual was succeeded by a feever which however fortunately abated in some measure by sunrise the next morning.” On 7 July 1805, Lewis reported that York was showing symptoms of “intermittent fever.”

Capt. Clarks black man York is very unwell today and he gave him a doze of tartar ememtic which operated very well and he was much better in the evening.     this is a discription [prescription] of medecine that I nevr have recourse to in my practice except in cases of the intermittent fever.

Sergeant Gass had an attack of chills on the night of 9 October 1805. He complained of having had “a fit of the ague,” and felt too weak the following day even to steer his canoe. He didn’t mention any alternating feverish spells, so the chills may have been symptoms of some other ailment. But if he really was suffering from malaria, it may have been a chronic form of the disease that he had contracted before he joined the expedition.

Today, in tropical regions such as East Africa, hundreds of people still die of malaria every day. Preventive methods consist mainly in the distribution of mosquito netting to protect sleepers from female Anopheles. Since the early decades of the twentieth century, people who live in temperate zones have been free of the scourge of malaria, but many scientists believe that with the onset of global warming, the eventual return of the Anopheles mosquitoes to the middle latitudes carrying protozoan parasites that cause malaria, is a distinct possibility.^[2]“Warming Trend May Contribute to Malaria’s Rise,” Science Daily (22 March 2006); http://www.sciencedaily.com/releases/2006/03/060322142101.htm (retrieved 19 July 2008).

Yellow fever, caused by a flavivirus (“yellow virus”) carried by Aedes aegypti, is believed to have originated in the savannas of Africa and the tropical Americas. It became a major scourge in North America beginning with the epidemic that struck the Massachusetts Bay colony in 1647. The yellow fever epidemic of 1793, which claimed 5,000 lives in Philadelphia alone, is still considered one of the severest medical disasters in American history.^[3]The story of the disaster, including the role of Meriwether Lewis’s tutor Dr. Benjamin Rush, is told in J. H. Powell’s Bring Out Your Dead: the Great Plague of Yellow Fever in … Continue reading The flavivirus was first identified in 1928, and a vaccine was produced in 1937, but no cases of yellow fever have been reported in the U.S. since 1905.^[4]Richard H. Foote and David R. Cook, Mosquitoes of Medical Importance, Agriculture Handbook No. 152, Agricultural Research Service, U.S. Department of Agriculture (July 1959), xx.

West Nile and Zika

The only mosquito-borne viruses recorded in the U.S. since the mid-twentieth century are several varieties of equine encephalitis, which was first isolated in 1933, and West Nile virus (WNV), first identified in 1937. Equine encephalitis occurs naturally in a great number of wild song birds, and is transmitted by mosquitoes–chiefly Culex pipiens –among birds and horses as well as humans. It is fatal to both horses and humans, but whereas it is a serious threat to livestock, fewer than a handful of human cases are recorded annually.

The first outbreak of West Nile virus in the Western hemisphere occurred in New York City in 1999. There is as yet no vaccine for it, nor even any specific treatment. Within the first nine months of 2002, 269 people were diagnosed with West Nile Virus in the U.S., and thirteen died from it.^[5]USGS Disease Maps 2008, at http://diseasemaps.usgs.gov/. Growers’ Guide, Ag News, September 2002, http://www.growersguide.com/ag_newssept02f.htm (accessed 26 April 2008).] Satellite imagery has been employed to map the geographical regions most favorable to the mosquitoes that are vectors of West Nile Virus. Mosquito habitat distribution maps may be found in the NASA News Archive.

The Zika virus, mostly carried by Ae. aegypti and Ae. albopictus, is moving north and south from it base in equitorial regions. It has made an appearance in the southern United States. At risk are primarily pregnant women as the virus can pass to the fetus causing birth defects. There is no vaccine or cure for Zika other than reducing the risk of being bitten.^[6]“Zika Virus,” Centers for Disease Control and Prevention, accessed 6 April 2018, https://www.cdc.gov/zika/index.html.

Expedition Preventions

In the spring of 1804 Lewis wrote to Clark from St. Louis: “I send you by Colter and Reed 200 lbs of tallow which you will be so good as to have melted with 50 lbs of hog’s lard, cooled in small vessels and put into some of those small Keggs which were intended for whiskey.” Then, on 12 June 1804, three weeks after heading upriver from St. Charles, the captains hailed a passing St. Louis-bound trader and bought 300 pounds of voyageurs’ grease from him.^[7]Moulton, Journals, 2:294. It is possible that the lard and grease served both to add nutrition to their daily meals, and to protect them from mosquitoes, but the first use was more important.

Meriwether Lewis and his men met a company of Lemhi Shoshone warriors on 13 August 1805–the height of mosquito season in the Rockies–and remark-ed, “these men then advanced and embraced me very affectionately in their way which is by puting their left arm over you wright sholder clasping your back, while they apply their left cheek to yours and frequently vociforate the word âh-hi’-e, âh-hi’-e     that is, I am much pleased, I am much rejoiced.    bothe parties now advanced and we wer all carresed and besmeared with their grease and paint till I was heartily tired of the national hug.”

David Thompson’s Remedy

David Thompson, who was a contemporary of Lewis and Clark, made a similar observation:

Oil is the only remedy and that frequently applied; the Natives rub themselves with Sturgeon oil, which is found to be far more effective than any other oil. . . . A sailor finding swearing of no use, tried what Tar could do, and covered his face with it, but the musketoes stuck to it in such number as to blind him, and the tickling of their wings were worse than their bites; in fact Oil is the only remedy.^[8]J. B. Tyrrell, ec., David Thompson’s Narrative (Toronto: The Champlain Society, 1915), 25-26.

Pierre-Jean de Smet’s Advice

Some fifty years later, the Jesuit missionary Pierre-Jean de Smet (1801-1873), the founder in 1841 of the first white settlement in what is now Montana, wrote of God’s vicious little creatures with about as much pious restraint as the tiny devils deserved.

And what shall I say of musquitoes? I have suffered so much from them, that I cannot leave them unnoticed. In the heart of the prairie they do not trouble the traveller, if he keep aloof from the shade, and walk in the burning sun. But at nightfall they light on him, and hang on him till morning, like leeches sucking his blood. There is no defence against their darts, but to hide under a buffalo skin, or wrap oneself up in some stuff which they cannot pierce, and run the risk of being smothered.

When green or rotten wood can be procured, they may be driven away by smoke, but in such case the traveller himself is smoked, and in spite of all he can do, his eyes are filled with tears. As soon as the smoke ceases, they return to the charge till other wood is provided and thrown on the fire, so that the traveller’s sleep is frequently interrupted, which proves very annoying after the fatigue of a troublesome journey.^[9]Pierre-Jean De Smet, S.J., Letters and Sketches with a Narrative of a Year’s Residence Among the Indian Tribes of the Rocky Mountains (Philadelphia: M Eathian, 1843), in Reuben Gold Thwaites, … Continue reading

Indeed, various oils and greases, mosquito biers (pron. barz, see Mosquito Netting), and smoke remained the standard ways to disappoint mosquitoes until citronella oil was approved as a biopesticide in 1948. It was extracted by steam distillation from tropical grasses of the genus Cymbopogon, a member of the sweet grass family. The drawback of citronella-based repellents is their limited period of effectiveness, which ranges from only 30 minutes to a maximum of 2 hours.