Longitudinal monitoring of Ehrlichia ruminantium infection in Gambian lambs and kids by pCS20 PCR and MAP1-B ELISA.

BACKGROUND: The epidemiology of E. ruminantium infection in extensively managed young animals is not adequately understood. Thus in this study, we monitored the onset (age at first infection) and kinetics of E. ruminantium infection and antibody response in extensively managed newborn lambs and kids at three sites in The Gambia. METHODS: We used a nested pCS20 PCR and MAP1-B ELISA in a longitudinal study to monitor the onset (age at first infection) and kinetics of E. ruminantium infection and antibody response respectively, in 77 newborn lambs and kids under a traditional husbandry system at three sites (Kerr Seringe, Keneba, Bansang) in The Gambia where heartwater is known to occur. The animals were monitored for field tick infestation and the comparative performance of the two assays in detecting E. ruminantium infection was also assessed. RESULTS: The infection rate detected by pCS20 PCR varied between 8.6% and 54.8% over the 162-day study period. Nineteen per cent of the animals in week 1 post-partum tested positive by pCS20 PCR with half of these infections (7/14) detected in the first 3 days after birth, suggesting that transmission other than by tick feeding had played a role. The earliest detectable A. variegatum infestation in the animals occurred in week 16 after birth. Antibodies detected by MAP1-B ELISA also varied, between 11.5% and 90%. Although there is considerable evidence that this assay can detect false positives and due to this and other reasons serology is not a reliable predictor of infection at least for heartwater. In contrast to the pCS20 PCR, the serological assay detected the highest proportion of positive animals in week 1 with a gradual decline in seropositivity with increasing age. The pCS20 PCR detected higher E. ruminantium prevalence in the animals with increasing age and both the Spearman's rank test (rs = -0.1512; P = 0.003) and kappa statistic (-0.091 to 0.223) showed a low degree of agreement between the two assays. CONCLUSION: The use of pCS20 PCR supported by transmission studies and clinical data could provide more accurate information on heartwater epidemiology in endemic areas and single-occasion testing of an animal may not reveal its true infection status. The view is supported because both the vector and vertical transmission may play a vital role in the epidemiology of heartwater in young small ruminants; the age range of 4 and 12 weeks corresponds to the period of increased susceptibility to heartwater in traditionally managed small ruminants.

Point seroprevalence survey of Ehrlichia ruminantium infection in small ruminants in The Gambia.

Using the MAP1-B enzyme-linked immunosorbent assay, we tested 1,318 serum samples collected from sheep and goats at 28 sites in the five divisions of The Gambia to determine the Ehrlichia ruminantium seroprevalence rates and to assess the risk for heartwater. About half (51.6%) of 639 sheep were positive, with seroprevalence rates per site varying between 6.9% and 100%. The highest seroprevalence was detected in the western part of the country (88.1% in the Western Division and 62.1% in the Lower River Division). Sheep in the two easterly divisions (Central River and Upper River divisions) showed the lowest seroprevalence of 29.3% and 32.4%, respectively, while those in the North Bank Division showed an intermediate prevalence of 40.6%. In goats, less than one-third (30.3%) of 679 animals tested were positive. The highest seroprevalence was detected in goats in the North Bank Division (59%) and Western Division (44.1%). Goats in the Lower River Division showed an intermediate level of 21.9%, whereas the lowest rates were found in the eastern part of the country (4.8% in the Central River Division and 2.3% in the Upper River Division). At nearly all sites, seroprevalence rates were higher in sheep than in goats. The results show a gradient of increasing heartwater risk for susceptible small ruminants from the east to the west of The Gambia. These findings need to be taken into consideration when future livestock-upgrading programs are implemented.

Application of field methods to assess isometamidium resistance of trypanosomes in cattle in western Ethiopia.

This study assessed the degree of isometamidium resistance of trypanosomes infecting cattle in the upper Didessa valley of western Ethiopia. An initial prevalence study was conducted to identify sites with a high risk of trypanosmosis in cattle. The trypanosome prevalence varied widely, with two sites, Kone (21.3%) and Village 1 settlement (15%) having a relatively high prevalence based on the phase-contrast buffy-coat technique (BCT). In the highest risk area, the Kone settlement, an isometamidium block treatment study was conducted from April to June 2001. A total of 300 cattle were included in this study, 100 from each of three villages (Cheleleki, Kolu and Burka). At day minus 14 of the study, all 300 cattle were treated with diminazene aceturate at 7 mg/kg body weight. Subsequently, these cattle were ear-tagged and randomly assigned into two groups, 50 controls and 50 for isometamidium treatment in each village. Fourteen days later (day 0), the 50 treatment cattle were given isometamidium chloride at 1 mg/kg body weight. Both groups of cattle were then examined for trypanosome parasites using BCT every 14 days until 84 days. The two indices used in assessing isometamidium resistance, namely the proportion of infections during an 8-week follow-up period and the ratio of mean hazards in an isometamidium treated versus untreated group, provided consistent results across the three villages. In Burka village, both indices demonstrated the presence of isometamidium resistance trypanosome infections while in Cheleleki and Kolu villages, both indices did not indicate significant levels of resistance. There were significant differences between the Kaplan-Meier survival estimates of the control and treatment groups in Cheleleki (P < 0.01) and Kolu (P < 0.05) but not in Burka (P > 0.05).

[Acute renal failure as a sequela of mushroom poisoning with Cortinarius speciocissimus]. / Akutes Nierenversagen als Folge einer Pilzvergiftung mit Cortinarius speciocissimus.

BACKGROUND: Poisoning with the mushroom Cortinarius speciocissimus is a rare event. Within 2-17 days after ingestion unspecific symptoms appear. Characteristically, this state is soon followed by irreversible kidney damage which finally requires chronic hemodialysis. CASE REPORT: A 46-year-old man was admitted with nausea, vomiting and acute anuria 9 days after he had eaten Cortinarius speciocissimus. Hemodialysis had to be started. Kidney biopsy revealed an interstitial nephritis. This finding corresponds to earlier case reports about intoxication with orellanine, the poison of Cortinarius speciocissimus. 6 months later the kidney function had not recovered leaving the patient to chronic hemodialysis. CONCLUSION: The prognosis of poisoning with that mushroom is poor. The amount of ingested poison is crucial. Monitoring of kidney function is mandatory when poisoning is suspected. Therapy is directed to symptoms. Usually dialysis has to be commenced. To rule out other causes for kidney damage, a kidney biopsy is required.