LOA LOA 



larvae taken from the uterus of L. loa ; (2) their geographical distri- 

 bution is the same as that of L. loa ; (3) they eventually occur in 

 the blood of patients suffering from Calabar swellings, a condition 

 due to L. loa. Their occurrence in the blood in this latter condition 

 and in L. loa infections we shall consider later. 



Periodicity. Here, as in the case of the larvae of Filaria bancrofti, 

 the larvae that appear in the blood 

 are probably the overflow simply of 

 the larvae which we assume, on 

 analogy, to have their principal site 

 in the lungs. They appear in the 

 blood about the time of getting 

 up, 6 to 8 a.m. (10 in 20 mm. 3 ), 

 at 12 noon there are twenty-four, 

 at 8 p.m. the number has fallen to 

 eighteen, and at midnight to one, 

 while from 2 a.m. to 6 a.m. none, 

 or one only, may be found. This 

 periodicity is, as a rule, a very 

 constant one, but there are excep- 

 tions, and in certain cases more 

 have been found at midnight than 

 at 9 a.m. The periodicity is also 

 lost in pathological conditions, 

 e.g., sleeping sickness (vide also 

 under Filaria bancrofti). The 

 possibility of non-periodic Loa loa 

 larvae should also be considered. 



Pathology. The parasite wanders 

 about the body, and may be seen 

 under the skin in thin parts. Their 

 advance is in some cases at the rate 

 of an inch in two minutes. During 

 their progress they give rise to 

 creeping sensations and to a con- 

 dition of transient cedematous areas 

 known as Calabar swellings on 

 various parts of the body, e.g., arm. 

 These vary in diameter from i to 



10 cm., and often shift their position an inch or so a day. They give 

 rise to a certain amount of redness, tension and heat, and their develop- 

 ment is promoted by muscular action of the part. They disappear to 

 reappear elsewhere. The condition is associated with a high eosino- 

 philia, 50 per cent, being not uncommon. Patients known to harbour 



FIG. 297. Mf. loa : in thick film, dried 

 and stained with hsematoxylin. x 1,000. 

 (After Fulleborn.) 



