A History of Mosquitoes in Massachusetts

Curtis R. Best

Central Massachusetts Mosquito Control Project, Northborough, Massachusetts

The earliest written record of pestiferous mosquitoes and their effect on human activity in Massachusetts dates back to the day of the Pilgrims. In 1623 a segment of the Pilgrim population sent a letter to the London merchants who were sponsoring the adventure. In the letter they listed the reasons why they thought the settlement should be relocated to better grounds. Chief among these reasons for resettling was that they "were much annoyed by mosquitoes".

In 1630 a party of pioneers gave up their settlement in what is now Charlestown, MA and moved to a peninsula in Boston Harbor to escape mosquitoes and there founded Boston.

Mosquitoes were not only a nuisance in the early days. They were a threat to human health as well.

The Peabody Museum here in Salem has a display which describes how Massachusetts ships would trade salted codfish for sugar in the Caribbean. The codfish was used to feed plantation slaves which had been brought from Africa. Yellow fever was endemic in regions of Africa and became so in the Caribbean. Ships plying the trade route from endemic areas to northern cities inadvertently carried the disease pathogen and its vector with them. During the 18th and 19th centuries sporadic outbreaks of yellow fever occurred in the urban areas of Massachusetts; typically during the summer months when the yellow fever vector would establish a temporary foothold in the region.

In 1847, a hospital for infectious disease was built on Deer Island, chiefly for Irish immigrants quarantined there with yellow fever.

In 1881, Dr. J. F. Adams in a report to the American Public Health Association on the occurrence of malaria in New England said that "when that portion of the country was first settled, fever and ague was one of the common diseases, being apparently incident to the clearing off of the forest".

Records from the latter part of the 1600's and until the late 1700's, though very incomplete and chiefly from non-medical sources, make no mention of malaria in Massachusetts.

However, in 1793 intermittent and remittent fever "as malaria was then known" reappeared in certain communities in western Massachusetts. This outbreak lasted until 1799. The town of Sheffield, Massachusetts experienced outbreaks of malaria in 1806,1810, and 1820.

"Malaria reappeared once again in western Massachusetts between 1828 and 1836. There were no reported cases of malaria in Massachusetts between 1836 and 1877 although it did appear in Connecticut."

"In 1877, following the river valleys from Connecticut northward, malaria began an invasion of western Massachusetts. Within four years time the disease penetrated almost to the northern border of the state."

"Prior to 1880, malaria in Massachusetts was limited to the western half of the state and to the towns bordering the east bank of the Connecticut River. Of the cases reported in 1880, 1,344 occurred in Hampden County, 300 in Hampshire County and 287 in Berkshire County. It is interesting to note that three-fifths of all the cases reported in the state during 1880 occurred in four contiguous cities two of which. Springfield and West Springfield, border the west bank and two, Chicopee and Holyoke, border the east bank of the Connecticut River."

In his report Dr. Adams points out that the communities where malaria occurred are "found to be, with scarcely an exception, on the borders of rivers, or adjacent to swamps, ponds or artificial reservoirs".

"It has thus shown a decided affinity for water." The question of what caused

had perplexed mankind for centuries. One theory held that stagnant water was the source of the disease. Dr. Adams, in his work, had made observations which led him to refute this theory and provide an alternative. He brings up his observations in his report.

"... on the banks of rivers the greatest number of cases have occurred where there are hy shores, overflowed in spring and laid bare in summer especially where low spots or obstructed ditches cause stagnant pools to form which are gradually dried up by the summer sun. Besides these areas the places most fertile in have been the reservoirs used for water power..."

"These reservoirs ... are very shallow and only full after the spring freshets. During the summer they become drawn down so as to expose great tracts of oozy bottom covered with rotting stumps and other vegetable matter. The greater the extent of the exposed surface the greater as a rule has been the prevalence of malarial fever; and, the evidence from all sources agrees in indicating that it is not water but mud which most powerfully influences its development."

In 1877, only four years prior to Dr. Adams' report to the A.P.H.A., Pasteur had formulated the germ theory of disease. Dr. Adams was familiar with the theory and believed that something in mud was the causative agent of malaria. Almost two decades would pass before malaria and its transmission were fully understood.

Pasteur's theory led to the extensive activity of the late nineteenth century and the first decade of the twentieth century which saw the birth of medical entomology as a science.

In 1889 and 1893, Dr. Theobald Smith made discoveries which implicated cattle ticks as the necessary developmental host of the causal agent of Texas cattle fever. The question of what caused malaria and how it was transmitted did not escape his attention. In 1896, he wrote this letter to one Dr. White of Uxbridge, Massachusetts which was in the midst of a malaria outbreak.

June 30, 1896

Dear Doctor:

Your published letter has been received and read with much interest. I think that you state the situation as clearly as it can be made out at the present time. I wish to state in a few words what I am at present considering as a working hypothesis but I do not care to have it published or discussed at present as I have no evidence to back it up. I simply make the suggestions for your own use as Health Officer.

I believe that the malarial germ is caused by mosquitoes, not all mosquitoes to be sure but only those in infected localities. Anything that favors the breeding of these pests like stagnant ponds, pools, sewers, etc. would favor it.

I wish that your boy would catch for me some of the Uxbridge mosquitoes and send them to me alive in a box with pinholes in them. I wish to compare them with those in this non-infected neighborhood.

In your work of suppression, I would suggest that you keep your mind on these insects. Devise protection by window screens, in-door (illegible) abandonment of barrels, tubs, etc. about the house that contain water in which they breed abundantly.

However this hypothesis will be found true I do not at present know. The State Board is not prepared to make any public statement so I wish you to keep the letter as a confidential matter.

I regret that my work here does not permit me to spend (more or some) time at Uxbridge.

But if you keep me informed I can make suggestions from here. I also wish that you would continue to send me (preparations) when opportunity offers.

Very truly yours,

Theobald Smith

That same year, 1896, the Neponset River basin was implicated as a source of malaria in the Boston area. While mosquitoes were recognized as a nuisance to the public well being in this situation, they still had not been linked to the transmission of the disease. At the same time Irish and Italian immigrant laborers constructing the Cochituate and Wachusett Reservoir aqueducts to Boston were ravaged by malaria.

Important breakthroughs in medical entomology were imminent. In 1899, Grassi, Bignami and Bostinelli proved that the human a parasites were transmitted by a particular genus of mosquitoes, Anopheles; and Sambon and Low, in 1900, demonstrated the fact of transmission without a doubt.

By 1914, the epidemiology of malaria was better understood and it became a reportable disease in Massachusetts. Between 1915 and 1921, 550 cases of malaria were reported in Massachusetts, 31 of which resulted in death.

During the 1920's, it was realized that nuisance mosquitoes were hampering the development of the Cape Cod resort industry at great loss to economic potential.

Cases of malaria continued to appear in Massachusetts during the 1930's. In 1931, forty cases were reported; however, only two of these were thought to be endemic and the remainder imported.

In 1938 Eastern Equine Encephalitis was recognized for what it was when an outbreak in Massachusetts resulted in human and equine deaths.

In 1945 it was feared that returning war veterans would reintroduce malaria into Massachusetts but this proved not to be the case.