Abstract
“Sennetsu” is a well known endemic disease to cause a high fever accompanying enlargement of subcutaneous lymph nodules in Kyushu especially in Kumamoto, Miyazaki and Fukuoka Prefectures. According to the Ohtawara's report the disease would give positive Paul-Bunnel (PB) reaction, might be caused by a filtrable agent and might be the same to the glandular fever described by Pfeiffer. In the past few years a rickettsia-like body agent, however, was isolated from the patients which was nominated by Misao as Rickettsia sennetsu and by Fukuda as Rickettsia todai respectively differentiating from Rickettsia orientalis mainly through the cross challenge test in human volunteers and in animal experiments. Contrary to it the agent was described by another investigators to be Rickettsia orientalis. Furthermore, the disease could be cured by the administration with some antibiotics and it was said that a rise of titer in both Weil-Felix reaction against OXK and PB reaction was given on paired sera from the patient. Consequently it seems unlikely that “Sennetsu” in Kyushu can be the infectious mononucleosis.
On the other hand it has been made clear by Dr. Tamiya and his associates that scrub typhus patient might exsist over all Japan in any season especially in summer and the winter. Then it was necessary to elucidate relationship between scrub typhus and “Sennetsu”. Prior to differentiate scrub typhus from “Sennetsu”, attempt was made as to whether or not Rickettsia orientalis might contain a Forssman (F) antigen and whether the scrub typhus patient might give positive PB reaction on sera collected from scrub typhus patients as well as inoculated animals.
The results were obtained as follows.
1. A rise of titer of PB reaction in 20 rabbits weighing 2.5-3.0kg was seen on 1st to 3rd weeks sera among those collected weekly until the 9th week following intra-ocular, -testicular and -dermal inoculation with mouse organ emulsion infected with 10 field rodent strains and 3 patient strains of Rickettsia orientalis and then fell down. Such positive turned in negative after absorption with guinea pig kidney but the titer did not change in 2 samples and fell down by 1/2 to 3/4 in 7 samples after absorption with cow red cells according to Davidsohn's test.
2. The similar results were obtained on sera from 6 rabbits inoculated with normal mouse organ emulsion.
3. No rise of titer of PB reaction was obtained in 6 rabbits inoculated with infected rabbit testicular emulsion which was proven not to contain any F antigen. From the foregoing results it was seen that the rise of titer of PB reaction in rabbits 1) and 2) was caused by F antigens contained in mouse organ emulsion and Rickettsia orientalis may not contain any F antigen.
4. Low titer of positive PB reaction was seen on sera from 3 rabbits inoculated with infected HeLa cell suspension. Presumably it was caused by calf serum added to the culture media which was known to contain F antigens.
5. Sera from 3 guinea pigs containing F antigens did not show any positive PB reaction following intraperitoneal inoculation with normal mouse organ emulsion.
6. PB reaction on sera from 3 albino rats not to contain any F antigen resulted in negative following intraperitoneal inoculation of mouse organ emulsion infected with 2 field rodent strains respectively.
7. The rise of titer of PB reaction was seen in 4 out of 7 healthy volunteers following intradermal inoculation of normal mouse organ emulsion. The results on sera after Davidsohn's test were obtained similary to 2) in rabbits. No relation was found between a rise of titer of PB reaction and blood types especially Aiv factor.
8. The significant rise of titer of Weil-Felix reaction was given on paired sera among 20 serum samples collected from 16 scrub typhus patients in Niigata Prefecture in 1955, while sera gave a low titer O-1: 28 of PB reaction.
9. Out of 9 healthy
