INSECTS AND DISEASE Department of the Moselle. In the years following the Napoleonic wars the disease broke out from time to time in different parts of the country, and showed special incidence among the inmates of convict prisons and local jails. In 1848 an outbreak of typhus was started by a prisoner at Amiens, who infected the judge, the clerk of the court, as well as several Sendarmes and prisoners. Similar outbreaks occurred at Rheims, Toulon and elsewhere in connection with civilian prisoners. | “The next importation of typhus fever to France on a large scale by troops occurred on the return of the French military forces from the Crimea, where they had suffered severely from the disease. It is reported that out of an effective force of 120,000 men at least 12,000 were attacked by typhus during the campaign, and that half that number died.
“Following upon the return of the troops, outbreaks of typhus occurred at Marseilles, Toulon, Avignon, Paris and elsewhere.” Gradually and without any intelligently directed effort to control its spread, but apparently as a by-product of the generally improved sanitary conditions of living, typhus fever almost disappeared from civilized countries. ‘““T'yphoid”’ fever, named from its resemblance to the more deadly typhus, with which it was once confused, remains a serious menace, but typhus was almost forgotten in western Europe until war broke out in 1914. The table below from Doctor Bruce Low shows how the deaths from this disease have decreased in England and Wales and in Ireland.
DEATHS FROM TYPHUS FEVER IN England and Wales Ireland 1869-1883 23,702 11,544 1884-1898 2,249 4,703 1899-1913 390 1,043 In certain parts of the world, however, where sanitary conditions remain primitive, typhus has held its own. It has occasionally found its way into central Europe from Poland and Galicia. In many districts of Mexico it has long been a serious scourge; and an infection, known as Brill’s disease, which occurs in New York City, has been shown to be a mild form of typhus.
Many of the characteristics of typhus fever pointed to the probability of an insect carrier, and suspicion was finally fastened upon the louse as the most probable culprit. The coincidence between 61
the seasonal and geographical distribution of the disease and the insect, in particular, seemed significant, high temperature apparently being inimical to each. At last in 1909 Nicolle, Comte and Conseil succeeded in transmitting typhus fever to monkeys by the bite of the body-louse. This result was confirmed in the next year in this country by Ricketts and Wilder; and Goldberger and Anderson showed that not only the body louse (Pediculus vestimenti) but also the head louse ( Pediculus capitis) may transmit the specific infection. As an illustration of the danger to which those who work on the insect-borne diseases are exposed, it may be noted that one of this sroup of devoted experimenters, Howard T. Ricketts, contracted the disease in the course of his investigations and died, almost at the outset of a brilliantly promising career.
With the outbreak of the European War in 1914, typhus again came into public notice as it broke out in malignant form on the eastern battle-front. Its effects upon the course of campaigns in the Balkans is said to have been very material; but the French, German and Russian armies have been protected against its ravages by elaborate provisions for the destruction of lice by the disinfection of clothing and the cleansing and disinfection of the person, particularly of the hair.
The body louse usually conceals itself in the folds of the clothing, depositing its eggs along the seams and wrinkles. A female may deposit nearly 300 eggs which hatch in 3-4 days and reach maturity in 15-18 days. According to recent studies reported in English medical journals,” lice are able to live without food for 2-6 days. They become rigid with cold at 10° F. and are killed in 2-6 hours at 104° F. Among the various substances which have been employed for the destruction of lice, the most efficient appear to be a killing powder composed of 96 per cent. naphthalene, 2 per cent. creosote, and 2 per cent. iodoform, and an ointment known as vermijelli. The soldier’s clothing and equipment may be freed from lice by treatment in either dry or moist heat sterilizers or in special sterilizers which make use of the simultaneous effect of heat and formaldehyde in vacuo. Ironing the seams of garments with a hot iron is a simple and generally effective method. Military encampments are usually provided with special stations for ““delousing”’ or “‘depediculization, ” An excellent review of recent contributions to the biology of the louse is to be found in ‘‘Household and Camp Insects’’ by E. P. Felt, Bull. No. 194, New York State Museum.
62 .
: INSECTS AND DISEASE so arranged that while the men are being bathed their clothes are simultaneously freed from lice by one of the methods described above.
In addition to typhus, a form of relapsing fever is not uncommonly spread in Russia and in other countries of southeastern Europe by the bite of the louse, and this disease has offered one of the serious problems of army sanitation on the eastern front.
AMERICAN MUSEU./ GUIDE LEAFLETS OTHER DISEASES TRANSMITTED BY ARTHROPODS In addition to the insect-borne diseases mentioned above, there are many other diseases of tropical countries, which are transmitted in a similar way by insects or by their relatives, the ticks. Among the most important of these are sleeping sickness and other diseases caused by the Protozoan parasites of the genus 77rypanosoma, and transmitted by the biting flies of the genus G/ossina, and certain forms of relapsing fevers and similar maladies, caused by spirochetal parasites transmitted by ticks.
A ey iy, ss aa Fig. 34. DISTRIBUTION OF TEXAS FEVER OF CATTLE AND ROCKY MOUNTAIN TICK FEVER The ticks are not insects at all but belong to the Acarina or mites (see page 4). The first of all the arthropod-borne diseases to be definitely worked out was the serious cattle plague, known in our Southwestern States as Texas fever and in Australia as redwater fever. In 1889 Smith and Kilbourne showed that the causative agent in this disease was a Protozoan parasite ( Babesia) and that it was carried by the bite of a tick, Boophilus annulatus. Rocky Mountain spotted fever, which attacks visitors to the Bitterroot Valley and other areas in the Mountain States, is spread by Dermacentor andersoni and other ticks. The most terrible of tick-borne diseases, however, are the African tick fevers or relapsing fevers caused by different species of spirochetes.
64 pe IS es ee e a a > el
INSECTS AND DISEASE Fig. 35. THE TSETSE FLY (Glossina morsitans) Fig. 36. TYPICAL BREEDING PLACE OF GLOSSINA ON THE BELGIAN CONGO 65
AMERICAN MOUSECOM-GUIDE LEAFLETS The head- and body-lice, as has been indicated, are the agents in the transmission of typhus fever and are probably active in the spread of European relapsing fever as well, while the body-louse is believed to play a part in the transmission of the special form of relapsing fever which occurs in northern Africa. Bed-bugs (Cimex) and assassin-bugs (Conorhinus) are probably the agents in disseminating Opilacao or Chagas fever in Brazil and Kala-azar or dumdum fever in India and China.
Of the trypanosome diseases, the most important are the cattle disease of South Africa, Nagana, carried by Glossina morsitans, and the sleeping sickness of man. It is estimated that between 1900 and 1910 there were 200,000 deaths from sleeping sickness in the Uganda Protectorate alone. The particular trypanosome which causes this malady is carried by another biting fly, Glossina palpalis, which lives in rather sharply limited areas of dense forest and undergrowth along the shores of lakes or rivers. Clearing the jungle for a hundred yards along the water courses and for three hundred yards about all villages, screening of houses, protection of the body against bites, and the isolation of the sick are among the most important preventive measures in use against this disease. Surra, a cattle disease of Asia, Malaysia, and the Philippines, somewhat similar to Nagana, is a trypanosome disease spread by various blood-sucking flies, while sand flies (Phlebotomus) carry the unknown germs of the Pappatici fever of the Mediterranean and Verruga in Peru. The suspicion that epidemic anterior poliomyelitis (infant paralysis) and pellagra are causally connected with biting flies (Stomoxys, Simulium) has, on the other hand, not been substantiated.
Among the mosquitoes, besides the various species of Anopheles, which carry the germs of malaria, and the Aedes, which transmits yellow fever, Culex fatigans spreads the virus of Dengue fever, and with other mosquitoes is the agent in transmitting the microscopic worms (Fi/aria) which cause elephantiasis and other forms of filariasis. 66
INSECTS AND DISEASE TRYPANOSOME :
Protozoan which causes Sleeping Sickness of Central Africa. Cn _ e | Bacillus of Bubonic Plague y LEISHMANIA Protozoan parasite which causes Indian kala-azar or dum-dum fever. Fig. 37. MODELS OF BLOOD PARASITES American Museum of Natural History 67
AMERICAN MUSEUM GUIDE LEAFLETS TABULAR REVIEW OF PRINCIPAL INSECT-BORNE DISEASES DISEASE PARASITE CARRIER ACARINA (mites) West African Tick Fever Spirocheta duttoni Ornithodorus moubata Rocky Mountain Spotted Fever i at Ee i A, Vk as Se ates Sere ee Malena Dermacentor andersont andotherticks Opilacao (or Chagas Fever) Trypanosoma cruzi O. moubata, also certain Hemiptera Texas Fever of cattle Babesia bigeminum Boophilus annulatus Spirochetosis of fowls Spirocheta gallinarum Argas persicus HEMIPTERA (bugs) a yplitis Mever s.)) -#i oy ss Le dae 2 tials eee ee ane Pediculus capitis, P. vestimentt Opilacao (or Chagas Fever) Conorrhinus megistus, of Brazil Trypanosoma cruzt Cimex lectularius, C. hemipterus,alsocertain ticks European Relapsing Fever Spzroch@eta recurrentis P. capitis, P. vestimenti . 9 . b also, perhaps, bedbugs North African Relapsing es PS, g Fever Spirocheta berber Pediculus vestimenti Kala-Azar or Dum-Dum ; Fever Leishmania donovant Conorrhinus rubrofasciatusorCimexhemipterus(?) SIPHONAPTERA (fleas) Bubonic Plague Bacillus pestis Xenopsylla cheopis and Infantile splenic : other fleas leishmaniasis Letshimania infantum Pulex trritans and other fleas DIPTERA (flies) Sleeping Sickness Trypanosoma gambiense Glossina palpalis Nagana disease of cattle Trypanosoma brucei Glossina morsitans and other flies Surra of cattle A filterable virus fhlebotomus papatasit Vemniparpemiviana. 6) AES cece Sree Phiebotomus verrucarum (?) Typhoid,diarrhealdisease of children, etc. Various bacteria Musca domestica (occasional accidental carrier) DIPTERA (mosquitoes) Malaria—tertian Plasmodium vivax | : ‘ quartan P. malarig Anopheles maculipennis zestivo-autumnal P. falciparum \ and other Anopheles sp. Yellow Fever A filterable virus Aédes calopus Filariasis Filaria bancrofti Culex fatigans, Anopheles nigerrimusandothers Dengue A filterable virus Culex fatigans 68