Splenomegaly and reticulocytosis caused by Babesia microti infections in natural populations of the montane vole, Microtus montanus.

A survey for Babesia microti in rodents was conducted at six sites within Grand Teton National Park, Wyoming. Blood and spleen smears, hematocrits, and reticulocyte counts were made on all of the animals to evaluate parameters for the diagnosis of babesiosis. Ticks were removed for identification. Of 257 Microtus montanus, 103 were infected with B. microti. In addition, five of 12 Microtus pennsylvanicus and one of three Arvicola richardsoni were parasitized by B. microti. Peromyscus maniculatus (n = 40) were not infected. Concurrent infections by Hepatozoon sp., Trypanosoma sp., and the bacterium, Grahamella sp., were noted in blood smears from a number of M. montanus. Splenomegaly and reticulocytosis were significant parameters associated with babesiosis while decreased hematocrit was not. Ticks removed from the voles were identified as Ixodes eastoni and were the probable vectors of the B. microti.

Redescription of flagellar arrangement in the duck intestinal flagellate, Cochlosoma anatis and description of a new species, Cochlosoma soricis n. sp. from shrews.

Cochlosoma anatis Kotlán (Zoomastigophorea, Retortamonadida, Cochlosomidae), isolated from the large intestines of domestic Rouen ducks, and Cochlosoma soricis n. sp., isolated from the small intestines of shrews, were observed by light and scanning electron microscopy. In both organisms, a single flagellum inserted on the dorsal surface at the same level as the insertion of 4 other flagella on the ventral surface. The 4 ventro-lateral flagella emerged from the left side of the anterior attachment disk below the margin and just above the lateral groove which extended the length of the organism. A 6th flagellum emerged from the margin of the attachment disk. The proximal ends of the flagella formed a bundle with the distal ends becoming unraveled like a rope. During motility, the bundle portion extended straight out from the cell and the free ends of the flagella produced a whipping motion. In C. anatis, the dorsal surface was covered with knob-like lumps and small pits and the cells had an axostyle that emerged slightly to the right of the midline in the posterior 1/3 of the body. The axostylar tip was shorter and thicker than the flagella and in most cells it also had an irregular, knobby appearance. The irregular cell surface and axostyle were absent from C. soricis. The margin of the attachment disk curved toward the center and terminated in C. anatis as a straight edge while in C. soricis it continued as a spiral. Indentations in the mucosal brush border similar to those produced by Giardia, but distinctly belonging to Cochlosoma, were interpreted as points of attachment to the host.

Intestinal parasites of small mammals from Grand Teton National Park.

A study of the prevalence and identity of Giardia spp. in small mammals of Grand Teton National Park was undertaken. All 90 montane voles examined were positive for Giardia, as were 4 pocket gophers, 1 water shrew, 4 water voles, and 2 meadow voles. How and why these findings contrast with the findings of others are discussed.

Effects of hormones and gonadal status on the midventral gland of the grasshopper mouse Onychomys leucogaster.

A midventrally located fusiform sebaceous gland is found in the northern grasshopper mouse Onychomys leucogaster. Microscopically, the gland consists of numerous multilobular units. Copious secretory material collects in the central duct of each unit and is extruded to the outside. The gland is larger in the male than in the female. Castration causes an involution of the gland in both sexes. Testosterone propionate (1.0 mg/0.1 cc olive oil, subcutaneously every other day for 4 weeks) restores the gland to full activity in castrates of both sexes. Estradiol benzoate (0.1 mg/0.1 cc olive oil, subcutaneously every other day for 4 weeks) has no effect on the midventral gland of ovariectomized females. A long photoperiod (18 L/6 D) leads to the development of testes, ovaries, and uteri that are significantly heavier than those of animals from a short photoperiod (6 L/18 D) regime. Midventral glands in animals of both sexes from the long photoperiod are larger and more active than glands from animals from the short photoperiod. The secretions of the midventral gland of Onychomys are probably used for communications such as territorial marking, advertisement of gonadal status, or pup identification.