The Animal Parasites of Man. Max Braun

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СКАЧАТЬ of L. tropica is unknown. Wenyon (1911)127 has found that the parasite develops into the flagellate stage in the digestive tract of Stegomyia fasciata in Bagdad. Patton (1912)128 has found similar development in the bed-bug in Cambay. The house-fly, Phlebotomus and Simulium have been suspected as transmitters in different parts of the world.

      An interesting announcement has been made recently (May, 1913), that Neligan has found that L. tropica occurs in dogs in Teheran, Persia, producing ulcers on the dogs’ faces (cf. natural occurrence of L. infantum in dogs—see p. 110). Yakimoff and Schokhor (1914),129 have found the disease in dogs in Tashkent.

Gonder130 (1913) has performed some interesting experiments showing the relation of infantile kala-azar to Oriental sore. Gonder infected mice with L. infantum and with L. tropica. He used culture material and injected intraperitoneally or intravenously. In each a general infection resulted, with enlargement of the liver and spleen. Later, however, mice injected with Oriental sore (North African variety) developed peripheral lesions on the feet, tail and head, and the lesions contained Leishmania. No such peripheral lesions developed in the case of the mice infected with the kala-azar virus. Gonder suggested that Oriental sore, like kala-azar, is really a general infection overlooked in its earlier stages, and that it is in the later stages that peripheral lesions on the skin are developed. Row (1914)131 also obtained a general infection in a mouse by the injection of cultures of L. tropica from Oriental sore of Cambay.

      Leishmania infantum, Nicolle, 1908.132

      Infantile splenic anæmia has been long known in Italy. It also occurs in Algeria, Tunis, Tripoli, Syria, Greece, Turkey, Crete, Sicily, Malta,133 Spain and Portugal. This leishmaniasis is, then, distributed along the Mediterranean littoral; also in Russia. Cathoire (1904) in Tunis and Pianese (1905) in Italy were among the first to see the parasite. Nicolle then found the parasite in patients in Tunis, and further found spontaneous infection in dogs. The patients are usually children between the ages of 2 and 5 years. There are a few cases known in which the infantile type of leishmaniasis occurred in youths and adults of the ages of 17 to 19, while one patient in Calabria was 38 years old. The symptoms are like those of Indian kala-azar. Several Italian investigators and others consider that L. infantum is the same as L. donovani, and that the latter name should be used for the parasite of Mediterranean leishmaniasis. This view, as to the identity of L. donovani and L. infantum, seems coming into general favour.

There are, however, differences between the Indian and infantile kala-azars, in addition to the ages of the patients affected, thus: (a) As regards cultures, it is found that L. infantum is readily grown on the Novy-MacNeal-Nicolle (“N.N.N.”) medium (saline blood-agar), and that sub-cultures are easily obtained; in citrated blood L. infantum grows with difficulty. The reverse is the case with regard to culture media for L. donovani, which grows with difficulty on the N.N.N. medium, but relatively easily in citrated splenic blood. (b) Considering inoculability into experimental animals, it is found that L. donovani is inoculated generally with some difficulty into white rats, white mice and monkeys, and with greater difficulty into dogs, while L. infantum can be inoculated into several experimental animals, especially into dogs and monkeys, with ease. (c) At present L. donovani is not known to occur spontaneously in animals, but L. infantum is found naturally in dogs in the Mediterranean region, and the disease in dogs is often referred to as canine kala-azar. Kittens have occasionally been found infected. However, these differences must not be emphasized too much.

      The material for cultivation is obtained from punctures of spleen, liver or bone-marrow of cases infected with L. infantum. It is not always easy, however, to infect from cultures, as the cultural flagellates inoculated into the body are often phagocytosed.

      Similarly, the material for animal inoculation is obtained from emulsions of infected spleen, liver or bone-marrow. Dogs and monkeys are easily inoculated with such material; Nicolle inoculates into the liver or the peritoneal cavity. Mice, white rats, guinea-pigs and rabbits only show slight infections after such inoculations.

      Dogs infected experimentally with infantile leishmaniasis may show either acute or chronic symptoms. The acute course occurs more often in young dogs, and is usually fatal in three to five months. The chronic course is found more commonly in older dogs, and may last seventeen to eighteen months. In acute forms there is irregular fever, progressive wasting, diarrhœa occasionally, motor disturbances involving the hind quarters, and the animal dies in a comatose condition. In the chronic form the animal may appear well, except for loss of weight. The parasites may be found in the internal organs of these experimental dogs, but are not numerous in the peripheral blood except at times of high fever. Experimental monkeys live about three months.

      It may be interesting to record the number of dogs found to be infected naturally with leishmaniasis in various countries. In Tunis, Nicolle and Yakimoff found about 2 per cent. infected out of about 500 dogs examined. Sergent in Algiers found 9 infected out of 125 dogs examined. In Italy and Sicily, Basile found about 40 per cent. of the dogs to be infected out of 93 examined at Rome and Bordonaro. Cardamitis found 15 infected out of 184 examined in Athens. In Malta, Critien found 3 infected out of 30 dogs examined. Alvares found 1 infected dog out of 19 examined in Lisbon. Pringault has recently (December, 1913) found an infected dog in Marseilles.134 Yakimoff and Schokhor found 24 per cent. infected out of 647 dogs examined in Turkestan.

      The distribution of the parasites in the body of the human patient is much the same as in the case of Indian kala-azar. Critien records the finding of parasites in the mucous flakes of the stools of a three-year-old Maltese child.135 Intestinal lesions rarely occur in infantile leishmaniasis.

      Ætiology.—Infantile leishmaniasis is stated to be transmitted by fleas, especially dog fleas, Ctenocephalus canis (= Pulex serraticeps), and by Pulex irritans. Children living in contact with infected dogs may be bitten by infected dog fleas, and so contract the disease. Basile (1910–11) and Sangiorgi (1910) state that they found L. infantum parasites in the digestive tract of the dog flea. After searching they found infected dog fleas on the beds, mattresses, and pillows used by children suffering from the disease. Franchini (1912) thinks that Anopheles maculipennis may be concerned in the transmission.

      Basile136 tried a number of experiments to show that infantile leishmaniasis is transmitted by fleas, thus:—

      (1) Fleas were taken from a healthy dog. They were placed in vessels containing infected spleen-pulp and allowed to feed thereon. The fleas were then killed and dissected, and portions of the gut-contents examined for parasites. The remainder of the gut was emulsified and injected into a young puppy, whose bone-marrow had been shown previously to be uninfected. Basile states that the puppy became infected. The parasites are said to increase in number in the flea’s gut.

      (2) Two healthy pups, each a month old, and born in the laboratory, were placed in a disinfected, flea-proof cage. A few days after, an infected dog was placed in the cage, so that fleas from the infected dog could pass on to the puppies. A month later the two pups became infected, parasites being found in them after liver puncture. A number of control puppies from the same litter remained uninfected and in good health.

      (3) Basile next used other laboratory-born puppies, a month old. Four of the litter were placed in a disinfected, flea-proof gauze cage in Rome. The cage was isolated from other dogs. Fleas obtained from an infected area in Sicily were placed in the cage. The puppies were examined by hepatic puncture, but were found to be negative for two months. Then two of the puppies showed infection, and six days later the remaining two puppies were found to be infected, and all four died. They showed irregular temperatures, and were getting thin. Control puppies remained healthy.

      From these experiments Basile concludes that fleas transmit leishmaniasis. СКАЧАТЬ