MALARIA may be defined as an infectious disease due to the presence in the blood of a parasite called Inematocytozoon malarite. It is char acterized by paroxysms of intermittent fever with enlargement of the spleen.
discovered the specific organism of malaria in 1SSO. It is an animal parasite belonging to the group of protozoa and attacks the red blood cells and for this reason is called a hiemacytozoon. There are three forms of the parasite, namely: tertian, quartan and the test ivo-autu in nal .
1. The tertian parasite completes its cycle of development in the human body in forty-eight hours. A double infection with the tertian parasite is common in children and is called the quotidian type of fever. When first seen it is a small oval particle within a red blood cell. This develops rapidly and in a few hours pigment may be seen around the periphery of the parasite. There is distinct amo2boid movement, pro trusions being put forth and then withdrawn. The Inemoglobin in the red cells fades while the pigment in the parasite increases. Just before the chill the parasite fills most of the red cells. Segmentation now takes place and the segments or spore forms are freed in the blood stream and are ready to attack new red cells and go through another cycle of development.
2. The quartan type is rare in the United States and takes seventy two hours to complete its cycle of development and the chill and fever are seen on every fourth day.
The early stages are like the tertian but on the third day the para site is quite still and the pigment is at the periphery.
3. The mstivo-autumnal variety is found in the more irregular fevers. It takes from twenty-four to forty-eight hours to complete its cycle and curious crescentic forms are seen after a week. There is but little pigment.
It is now definitely established that the parasite enters the blood through the bite of certain forms of mosquito. The mosquito is the intermediate host and two days after the mosquito has bitten the person whose blood contains the malaria parasite small refractive bodies may be seen in the stomach of the mosquito. Later, these burst into myriads of .spindle-shaped sporozoids and get into the salivary glands of the mos quito and thence infect the person bitten.
The parasite is only carried by the mosquito of the genus anopheles. The most common mosquito is of the genus culex. The two have dis tinctive characteristics. The anopheles has two large palpi, one on either side of the proboscis, and mottled wings. The harmless culex has small palpi and no spots on its wings. The anopheles, when on the wall or ceiling, holds its body away from the wall at an angle of 45 degrees or more, while the culex holds its body parallel to the van and usually the two hind legs are crossed over the back.
Malaria is endemic in certain localities. The role of the mosquito shows the reason for the liability to contract malaria after sunset, the danger from stagnant pools and marshes, the susceptibility of infants and young children and the greater frequency in the spring and summer.
mild eases of malaria there is little alteration in the structures of the body besides the changes in the blood and an enlarged spleen. Fatal cases are very rare in infants and children in this country.
In the severer and pernicious forms both the liver and spleen are enlarged and pigmented.
symptoms are apt to be most irregular and obscure in infants and young children. The typical adult types are found in children over six years of age.
Vomiting, chilly sensations and not infrequently a convulsion may usher in an attack. Distinct chills are not often seen in young children. They are replaced by cold hands and feet, blue lips and nails and drowsiness.
The quotidian type is the most common form although the tertian is not infrequent. The quartan and testivo-autumnal are very rare in the United States.
The fever is relatively higher than in adults and may reach 106° F. After from a half hour to four or five hours or longer the fever breaks and gradually falls to normal or below. The sweating stage is only slightly marked and may be entirely absent. When the fever falls the child feels weak but soon feels as well as usual. The child will feel well until the second paroxysm occurs. This is not so well marked as the first and the following ones even less so.