Synonyms: Piroplasma annulatum, Theileria annulata, Theileria dispar, Theileria turkestanica, Theileria sergenti.
Disease: Tropical gonderiosis, tropical theileriosis, tropical piroplasmosis, Egyptian fever, Mediterranean Coast fever.
Hosts: Ox, zebu, water buffalo. In addition, an American bison in the Cairo zoo died of a natural infection (Carpano, 1937).
Location: Lymphocytes, erythrocytes.
Geographic Distribution: North Africa, southern Europe, southern USSR, India, western China.
Prevalence: Tropical gonderiosis is one of the most important diseases of cattle in North Africa, southeastern Europe, southern USSR and Asia.
Morphology: The forms in the erythrocytes are predominantly (70 to 80%) round or oval, but may also be rodshaped, comma-shaped or even anaplasma-like. The round forms are 0.5 to 1.5 u in diameter, the oval ones about 2.0 by 0.6 u, the comma-shaped ones about 1.6 by 0.5 u, and the anaplasma-like forms 0.5 u in diameter. Binary fission with the formation of 2 daughter individuals or quadruple fission with the formation of 4 individuals in the form of a cross takes place.
The Koch bodies in the lymphocytes of the spleen and lymph nodes, or free in these organs, are similar to those of T. parva; they average 8 u in diameter but range up to 15 u or even 27 u. Two types are recognized: Macroschizonts, which contain chromatin granules 0.4 to 1.9 u in diameter and produce macromerozoites 2.0 to 2.5 id in diameter; and microschizonts, which contain chromatin granules 0.3 to 0.8 u in diameter and produce micromerozoites 0.7 to 1.0 u in diameter.
Life Cycle: The vectors of G. annulata are Hyalomma detritum (syn., H. mauretanicum) in North Africa and the USSR, H. truncatum in parts of Africa, H. dromedarii in Central Asia, H. excavatum (syn., H. anatolicum), H. turanicum (syn., H. rufipes glabrum) and H. marginatum (syns., H. savignyi, H. aegyptium) in Asia Minor, and H. marginatum in India. Transmission is stage-to-stage in all cases, and not thru the egg. Ray's (1950) and Kornienko and Shmyreva's (1944) claim of passage thru the egg has been disproved by Delpy (1949) and Daubney and Sami Said (1951).
The life cycle of G. annulata has been studied in H. detritum by Sergent et al. (1935). They admitted that they found no stages which could be identified as macrogametes or microgametes and that they saw nothing which could be recognized as fertilization, but they nevertheless believed that these must be present and called the subsequent stage a zygote. According to their account, the forms ingested by the tick are gametocytes. These form gametes in the tick's intestine, and the gametes in turn give rise to zygotes. The zygotes enter the intestinal epithelial cells, encyst, and remain in the lumen of the intestine for 6 to 8 months until after the nymphal tick has hibernated and molted to the adult stage. (H. detritum is a 2-host tick, with the larva and nymph on one host and the adult on the other.) At this time they leave the cyst and enter the salivary gland acini, where they penetrate the gland cells and turn into sporonts. These give rise to sporoblasts in 3 or 4 days, and the sporoblasts in turn produce a multitude of sporozoites which break out of the cells, enter the salivary ducts and are injected into a new host when the tick feeds. This life cycle is similar to that described by Cowdry and Ham (1932) for T. parva, and is subject to the same criticisms.
Pathogenesis: Tropical gonderiosis is similar to East Coast fever in most respects. The mortality varies considerably, from 10% in some areas to 90% in others. It is about 20 to 40% in Algeria, up to 90% in enzootic regions of the USSR and 13 to 23% in indigenous calves in India.
The incubation period following tick transmission is 9 to 25 days, with a mean of 15 days. The disease itself lasts 4 to 20 days, with a mean of 10 days. Peracute, acute, subacute, mild and chronic forms have been described. The acute form is the usual onea The first sign is fever, the body temperature rising to 104 to 107° F. The fever is continuous or intermittent, and persists for 5 to 20 days. A few days after it begins, other signs appear. These include inappetence, cessation of rumination, drooling, serous nasal discharge, lachrymation, rapid heart beat, weakness, decreased milk production and swelling of the superficial lymph nodes and of the eyelids. Marked anemia develops in a few days, and there may be hemoglobinuria. Bilirubinemia and bilirubinuria are always present. Diarrhea appears, and the feces contain blood and mucus. The conjunctiva is icteric and may bear petechial hemorrhages. Affected animals become greatly emaciated, and their erythrocyte count may drop below 1 million per cu mm. Death, if it comes, usually occurs 8 to 15 days after the onset.
In the peracute form of the disease, the animals may die in 3 or 4 days. In the subacute form, the fever is usually irregularly intermittent and lasts up to 10 or 15 days, after which the animals usually recover; pregnant animals sometimes abort. In the chronic form, intermittent fever, inappetence, marked emaciation and more or less anemia and icterus may persist for 4 weeks or longer, but it may take 2 months before the animals return to normal; in some cases, the acute form may suddenly supervene and the animals may die in a day or two0 In the mild form, little is seen but mild fever, inappetence, listlessness, slight digestive disturbances and lachrymation lasting a few days. There may be moderate anemia.
The lymph nodes are often but not always swollen; the spleen is often much enlarged. The liver is usually enlarged. Infarcts are usually present in the kidneys. The lungs are usually edematous, and characteristic ulcers are present in the abomasum and often in the small and large intestines.
Mixed infections with Babesia and/or Anaplasma are not uncommon; the resultant signs and lesions are then due to a combination of diseases and may differ from those described above.
Immunity: Animals which recover from G. annulata infections are premunized. There is no cross-immunity between G. annulata, G. mutans and T. parva.
Diagnosis: This is based upon finding and identifying the parasites in the erythrocytes in stained blood smears or in stained smears made from the lymph nodes or spleen. As mentioned under T. parva, differential diagnosis between theileriosis and the gonderioses is not always easy.
Cultivation: Tsur-Tchernomoretz (1945) cultivated the Koch bodies of G. annulata in ox tissue cultures thru 10 subcultures over a period of 2 months. Brocklesby and Hawking (1958) grew G. annulata in tissue culture for over 59 days, and the cultures were infective for cattle when tested after 42 days.
Treatment: No reliable drug is known for the treatment of tropical gonderiosis (Neitz, 1959).
Prevention and Control: Tick control by regular, repeated dipping is the most important control measure,, Quarantine measures, particularly with respect to importation of livestock from endemic areas into regions where suitable tick vectors exist, are also of great importance.
Immunization with a strain of low virulence has been used with success in North Africa and Israel (Sergent et al., 1945). The vaccine strain is maintained by serial passage in tick-free cattle. Animals are vaccinated by subcutaneous injection of 5 to 10 ml of citrated blood collected at the height of the febrile reaction. The blood should be used within 3 days after collection. The mortality following vaccination is usually less than 5%.