C.O. Njoku

Pathological changes in male genitalia of cattle infected with Trypanosoma vivax and Trypanosoma congolense.

Samples for histological studies were taken from the genitalia of 14 bulls (five infected with Trypanosoma vivax, five with T. congolense and four uninfected control animals), slaughtered 12, 22 or 30 weeks post-infection. Infection with Y58 strain of T. vivax and strain 2295 of T. congolense caused various grades of lesions in the male reproductive organs, especially the testes and epididymides. T. congolense produced more severe degenerative changes than T. vivax. It is concluded that in long-standing cases, the result of trypanosome infection is either serious infertility or even sterility.

Effects of experimental Trypanosoma vivax infection on first-, second-, and third-trimester pregnancy in heifers.

The effects of Trypanosoma vivax on pregnancy were studied in 18 heifers. The heifers were bred by a proven bull and divided into three groups of six heifers each. In the first group, four heifers were infected with T . vivax on Day 60 (first trimester) of pregnancy; two other pregnant heifers were uninfected controls. The second and third groups were similarly infected in the fourth (second trimester) and seventh (third trimester) month of pregnancy. One infected heifer in the first-trimester group aborted 39 days postinfection (p.i.); the remaining three had relatively normal gestation and parturition. In the second-trimester group, the pregnancies were carried to term with normal deliveries. In the third-trimester group, three infected heifers (75%) had premature deliveries while the fourth died about three hours after the full-term calf was pulled out. All of the control heifers had normal gestation and parturition. No gross abnormalities were seen in the placentae of the infected heifers, but histological sections of the heifers infected in the third trimester of pregnancy revealed more mononuclear cells than in those of the uninfected controls. Postmortem examination of the dead premature calves showed lymphadenopathy, splenomegaly, serous atrophy of perirenal and pelvic fat, epicardial petechiae, and blood-tinged peritoneal and pericardial fluids. Histologically, there were slight myocardial haemorrhages and edema. T. vivax was recovered from the blood of one of the premature calves. Both birth weights and PCV were affected by the experimental maternal infection in the first- and third-trimester calves. The birth weights and PCV of calves of infected dams were lower than those for the calves of the control heifers. This work therefore demonstrates transplacental transmission of T. vivax in heifers.

Comparative haematological changes following Trypanosoma vivax and T. congolense infections in Zebu bulls

A comparative study of haematological changes subsequent to Trypanosoma vivax and Trypanosoma congolense infections was carried out using 24 Zebu bulls during a period of 12 weeks. Eight bulls were infected with T. vivax, another eight with T. congolense and eight served as controls. Infected bulls developed chronic trypanosomiasis which was characterized by many clinical manifestations including intermittent pyrexia. Elevated rectal temperatures of up to 105 and 106 degrees F were recorded, respectively, in all bulls infected with T. vivax or T. congolense. Mean parasitaemia was higher and more chronic in T. congolense-infected bulls and ranged between means of 0 and 3.06 in all infected bulls. There was a slight and transient drop in packed cell volume (PCV) of T. vivax-infected bulls as against a marked and more chronic drop in T. congolense-infected bulls. Mean PCV of T. vivax- and T. congolense-infected bulls and controls ranged between 28 and 38, 17 and 38, and 31 and 38%, respectively. Haemoglobin (Hb) concentrations also decreased in infected bulls. The decrease was greater and more chronic in the T. congolense-infected bulls. Values ranged between means of 10.47 and 13.84, 5.44 and 14.16, and 10.24 and 14.12 g dl-1 in T. vivax- and T. congolense-infected and control bulls, respectively. Total plasma proteins also decreased in infected bulls; this was more marked in the T. congolense-infected group. Values for T. vivax-infected, T. congolense-infected and control bulls ranged between means of 7.66 and 8.99, 6.26 and 8.81, and 7.94 and 8.78 g dl-1, respectively.2+ that the indigenous T. vivax strains are more

Effects of experimental Trypanosoma vivax on fertility of heifers

Abstract Six heifers were used in a series of experiments to study the effects of experimental Trypanosoma vivax infection on bovine reproduction. Four three-year-old Zebu heifers were intravenously inoculated with T. vivax-strain Y58 — on days 14 and 16 of their estrous cycle and two control heifers in the same phase of estrus were not infected. All the heifers were bred in the research pens with a proven bull. The four infected heifers were bred at the first wave of parasitemia and the onset of pyrexia which characterised the infection. All the heifers were examined rectally 40 days after breeding. The four infected heifers were not pregnant but the two controls were. The infected heifers later became anestrous during the experimental period of more than five months. It is concluded that trypanosomiasis may contribute to high infertility rates in cattle kept in endemic areas.

Adrenal and thyroid dysfunctions in experimental Trypanosoma congolense infection in cattle

Severe pathological changes were observed in the adrenal and thyroid glands of Zebu (Bos indicus) heifers infected with Trypanosoma congolense. In the adrenal glands, severe inflammatory changes characterised by mononuclear cellular infiltration in the subcapsular areas, zona glomerulosa, zona fasciculata and zona reticularis were observed. In addition, there were hyperaemia, haemorrhage and hyperplasia resulting in increased adrenal weight in the two heifers slaughtered on Days 50 and 70 post-infection (p.i.). In the medullary areas of these two heifers, there was only mononuclear cellular infiltration. In the two heifers slaughtered on Day 113, localised mononuclear cellular infiltration was observed in addition to cortical cell depletion and fibrosis, resulting in reduced adrenal weight when compared with the controls. In the thyroid glands of the infected heifers, gross enlargement of the follicles filled with pale staining colloids were observed in association with squamous metaplasia of the follicular epithelium and fibroplasia. Serum cortisol concentrations showed an appreciable but non-significant increase (P less than 0.05) between Weeks 2 and 6 p.i. in the infected heifers (5.6 +/- 0.86 ng ml-1 vs. 4.4 +/- 0.34 ng ml-1) when compared with the uninfected controls or the pre-infection level. Thereafter, cortisol levels declined though non-significantly throughout the rest of the study. However, there was a steady increase towards normal levels from Week 12 p.i. until the end of the experiment. Changes in the basal serum concentrations of thyroxine (T4) were also measured weekly. There was a progressive decrease in the levels of T4 from the third until the 11th week p.i., when the decrease became significant (P less than 0.05) and remained so until the 16th week when the experiment ended.

Bacteriological investigation of the postpartum uterus: Relationship to involution and histopathological findings.

A bacteriological investigation of the postpartum uteri of suckled and nonsuckled Bunaji (White Fulani) cows was undertaken to determine the microflora, the effect of suckling on the flora and the influence of the flora on uterine involution and histopathology. Uterine contamination by bacteria was highest between days 10 and 21 postpartum with Staphylococcus aureus being the commonest organism isolated. There was no consistent isolation of one type of bacterial organism from a cow throughout the sampling period. Suckling did not affect the incidence of uterine contamination by bacteria. Foci of leucocytes (mainly lymphocytes) were found in uterine sections in an increasing frequency with days postpartum. Bacteria were isolated from only 3 of the 12 uteri that had the leucocytic foci. Uterine involution was normal and complete by 25 days after calving irrespective of the presence or absence of bacteria or leucocytic foci. We concluded that postpartum uterine contamination by bacteria was not influenced by suckling and that puerperal uterine contamination by bacteria did not interfere with the normal process and duration of uterine involution.

Seasonal and monthly variations in the incidence of morphological abnormalities in bovine spermatozoa in Shika, Zaria, Northern Nigeria

Morphological abnormalities of spermatozoa were evaluated in ejaculates of 27 healthy bulls aged between one and a half and three and a half years from January to December of 1982. The year was divided into three seasons: (1) January-April (partly harmattan, dry and hot), (2) May-August (rainy), and (3) September-December (dry and partly harmattan). All the bulls showed seasonal variations in the incidence of sperm-head abnormalities, detached-heads, proximal cytoplasmic droplets and total morphological abnormalities. The means for total morphological abnormalities of the spermatozoa were 21.5%, 10.6% and 11.3% for seasons 1, 2 and 3, respectively (P<0.01). There were also monthly variations in the incidence of morphological abnormalities of the spermatozoa. The monthly means for total morphological abnormalities of the spermatozoa ranged between 23.74% in March and 4.8% in September (P<0.001). The results indicated that there were significant seasonal and monthly variations in morphological abnormalities of spermatozoa and that the bulls may be most fertile and best used during the rainy season.

Elevation of morphological abnormalities of spermatozoa in the semen of Zebu bulls consequent to Trypanosoma vivax and Trypanosoma congolense infections

Twenty-four Zebu bulls were used in a 12-wk long study. Eight bulls were infected with T. vivax , eight others with T. congolense and eight bulls served as controls. All the infected bulls developed chronic trypanosomiasis. Mean percentage base-line values prior to infection for acrosomal, sperm-head, detached heads, proximal cytoplasmic droplets, distal cytoplasmic droplets, sperm-tail, midpiece and total sperm morphological abnormalities ranged between 0.1+/-0.1 for acrosomal and 8.7+/-3.4 for total morphological abnormalities in the semen of the bulls. These values were very low and within the range of those for fertile bulls. Following infection, there was a progressive increase in the mean values of all the abnormalities. Peak percentage mean values recorded for total sperm morphological abnormalities in the course of the investigation in the bulls infected with T. vivax and T. congolense and in the controls were 95+/-7.2, 100+/-0 and 7.9+/-5.0, respectively. Mean percentage values throughout the duration of the investigation for control bulls were low and within the normal range for fertile bulls. These values differed (P<0.001) from the elevated values of the infected bulls. The results indicate that trypanosomiasis due to either T. vivax or T. congolense infections can cause a marked increase in morphological abnormalities of spermatozoa which can, in turn reduce the fertility of breeding bulls.

Effect of chemotherapy on elevated ejaculation time and deteriorated semen characteristics consequent to bovine trypanosomiasis

The effect of the trypanocidal drug Novidium on elevated ejaculation time and deteriorated semen characteristics was studied in Zebu cattle infected with T. vivax and T. congolense. Two groups, comprising six bulls per group, were infected with Trypanosoma vivax or Trypanosoma congolense while three bulls served as controls. Chemotherapy was carried out 12 weeks post-infection on three bulls from each group, leaving three bulls untreated while three bulls served as uninfected controls. Blood samples from treated bulls were all negative for trypanosomes 3 days post-chemotherapy. The animals also had normal body temperature. As the study progressed, clinical signs associated with trypanosomiasis, such as anaemia and cachexia, disappeared gradually in treated bulls. There was some improvement in semen characteristics of some of the bulls at 10 weeks post-chemotherapy with Novidium. However, all bulls infected with T. vivax or T. congolense irrespective of Novidium chemotherapy still had poor semen characteristics manifested by all or some of the following: decreased volume of semen, oligospermia, azoospermia and elevated incidence of spermatozoa morphological abnormalities. They were thus unsuitable for breeding.

An abattoir survey of female genital disorders of imported camels (Camelus dromedarius) in Kano, Nigeria.

An abattoir survey of 850 female genital organs of imported camels was conducted at the Kano abattoir between October 1987 and April 1988. An incidence of 4.49% of disorders was recorded, including follicular cystic degeneration (0.12%), ovarian haemorrhagic cysts (0.47%), pyometra (0.35%), early embryonic mortality (0.12%), endometrial haemorrhages (0.47%), fetal maceration (0.12%), abscess (0.24%), vulvar tick infestation (1.77%) and cervical hypoplasia (0.12%).