A serological survey of leptospirosis in cattle of rural communities in the province of KwaZulu-Natal, South Africa.

A serological survey of leptospirosis in cattle originating from rural communities of the province of KwaZulu-Natal (KZN) in South Africa was carried out between March 2001 and December 2003. The survey was designed as a 2-stage survey, using the local diptank as the primary sampling point. In total, 2021 animals from 379 diptanks in 33 magisterial districts were sampled and tested with the microscopic agglutination test (MAT). The apparent prevalence at district level was adjusted for clustering and diagnostic test sensitivity and specificity and displayed in maps. The prevalence of leptospirosis in cattle originating from communal grazing areas of KZN was found to be 19.4% with a 95% confidence interval of 14.8-24.1%. At district level the prevalence of leptospirosis varied from 0 to 63% of cattle. Bovine leptospirosis was found to occur in communal grazing areas throughout the province with the exception of 2 districts. The southeastern regions showed a higher prevalence than other areas of the province; while in some of the northern and western districts a lower prevalence was noted. Several serovars were detected by the MAT and although Leptospira interrogans serovar pomona occurred most frequently, serovars tarrasovi, bratislava, hardjo, canicola and icterohaemorrhagica were also frequently identified. The findings of the survey are discussed.

Haemophilia A mutations in the UK: results of screening one-third of the population.

One-third of the UK haemophilia A population was screened to establish a national database of mutations and pedigrees and advance knowledge of the disease. The following mutations were found: 131 intron 22- and 13 intron1-breaking inversions; 11 gross deletions and an insertion; 65 frameshifts; three in-frame deletions and one insertion; 46 nonsense; 30 intronic mutations affecting splice sites and four generating new sites; 469 non-synonymous mutations due to 203 different base substitutions of which four affected, and nine were predicted to affect, splicing; three promoter mutations; two synonymous exon 14 mutations possibly affecting splicing; two VWF mutations. Of the above mutations, 176 are not listed in the Haemophilia A Mutation, Structure, Test and Resource Site (HAMSTeRS). Four gross deletions arose by non-homologous end-joining; we detected unexpected splicing in some mutations; substitution of amino acids conserved for less than 90 million years are rare; the risk of developing inhibitors for patients with nonsense mutations is greater when the stop codon is in the 3' half of the mRNA; changes likely to generate splice sites causing frameshifts are over-represented among non-synonymous mutations associated with inhibitors; our data and those in HAMSTeRS enabled the size of the spectrum of specific mutations causing the disease to be estimated and to determine how much of it is known.

A serological prevalence survey of Brucella abortus in cattle of rural communities in the province of KwaZulu-natal, South Africa.

A serological survey of Brucella abortus in cattle originating from communal grazing areas of Kwa Zulu Natal was carried out between March 2001 and December 2003. The survey was designed as a 2-stage survey, considering the diptank as the primary sampling unit. In total 46 025 animals from 446 diptanks of 33 magisterial districts were sampled and tested using the Rose Bengal test and Complement Fixation Test. The apparent prevalence at district level was adjusted for clustering, diagnostic test sensitivity and specificity, and mapped using ArcView version 3.3. The prevalence of brucellosis in communal grazing areas of Kwa-Zulu Natal was found to be 1.45 % (0.84-2.21%) and varied from 0 to 15.6 % between magisterial districts. In 19 of the 33 magisterial districts no serological reactors were observed. A large variation in prevalence was found within diptank areas. Brucellosis was found to be most prevalent in the northeastern area of the province. The findings of the survey are discussed.

A questionnaire survey of perceptions and preventive measures related to animal health amongst cattle owners of rural communities in KwaZulu-Natal, South Africa.

A questionnaire survey of 315 cattle owners from the rural districts of KwaZulu-Natal was carried out. The aim of the survey was to improve our understanding of local farmers' perceptions and practices of animal disease prevention and control and to establish the extent of their relationship with veterinary services. The survey showed that many owners practice preventive measures such as deworming, tick control and vaccination. Traditional medicines were in use by over half the respondents (58.9 %). Diseases are regarded as an important management problem (56.1 %); ticks, worms and diarrhoea dominated the mentioned health problems in cattle. Veterinary services still play an important role and are a frequent source of advice to owners. The findings of the survey and their context are discussed.

Int22h-related inversions causing hemophilia A: a novel insight into their origin and a new more discriminant PCR test for their detection.

BACKGROUND: Intrachromosomal, homologous recombination of the duplicon int22h-1 with int22h-2 or int22h-3 causes inversions accounting for 45% of severe hemophilia A, hence the belief that int22h-2 and int22h-3 are in opposite orientation to int22h-1. However, inversions involving int22h-2 are five times rarer than those involving its virtually identical copy: int22h-3. Recent sequencing has indicated that int22h-2 and int22h-3 form the internal part of the arms of an imperfect palindrome so that int22h-2, in the centromeric arm, has the same orientation as int22h-1 and, upon recombination with int22h-1, should produce deletions and duplications but not inversions. AIM: This work aims to provide rapid tests for all the mutations that can result from recombinations between the int22h sequences and to investigate whether int22h-2-related inversions causing hemophilia A arise in chromosomes, where the arms of the palindrome have recombined so that int22h-2 and int22h-3 swap places and orientation. PATIENTS/METHODS: Twenty patients with int22h-related inversions were examined together with a control and inversion carriers using reverse transcription-polymerase chain reaction (RT-PCR), long-range PCR and sequencing. RESULTS AND CONCLUSIONS: Analysis of mRNA in patients and a control provided evidence confirming the palindromic arrangement of int22h-2 and int22h-3 and the proposed inversion polymorphism that allows int22h-2 to be in the telomeric arm of the palindrome and in opposite orientation to int22h-1. New long-range PCR reactions were used to develop a single tube test that detects and discriminates inversions involving int22h-2 or int22h-3 and a two-tube test that can distinguish inversions, deletions, and duplications due to recombination between int22h sequences.

Start of UK confidential haemophilia A database: analysis of 142 patients by solid phase fluorescent chemical cleavage of mismatch. Haemophilia Centres.

A national strategy for optimising genetic services in haemophilia A has been initiated in the UK. Solid phase fluorescent chemical cleavage of mismatch is used to screen the entire coding region of factor VIII in six segments: four amplified from the trace of mRNA in blood lymphocytes and two from genomic DNA for the 3.4 kb exon 14 and flanking intron sequences. These segments are analysed in two threefold multiplexes so that the genes of 18 patients can be screened in a single ABI 377 gel. The promoter and polyadenylation signal region are amplified and sequenced directly. We have analysed 142 unrelated patients and identified 141 factor VIII mutations and one Normandy type von Willebrand homozygote. The former mutations include 89 missense, 10 nonsense, 5 frameshift, one 24 bp deletion and one splice signal defect. These comprise 71 different changes, of which 39 have not been previously observed.

Factor VIII inhibitors in mild and moderate-severity haemophilia A. UK Haemophilia Centre Directors Organisation.

Twenty six patients with mild or moderate haemophilia A and inhibitors are described. The inhibitor was detected at a median age of 33 years, after a median of 5.5 bleeding episodes. This usually following intensive replacement therapy. The median presenting inhibitor titre was antihuman 11.6 BU/ml, antiporcine 1.45 BU/ml. Plasma basal factor VIII level declined from a median of 0.08 IU/ml to 0.01 IU/ml following the inhibitor development. This caused spontaneous bleeding in 22 and a bleeding pattern similar to acquired haemophilia in 17. Bleeding was often severe and caused two deaths. The inhibitor disappeared spontaneously, or following immune tolerance induction, in 16 cases after a median of 9 months (range 0.5-46), with a return to the original baseline VIIIC level and bleeding pattern accompanied inhibitor loss. The inhibitor persisted in the remainder of the cases over a median period of 99 months (range 17-433 months) of follow-up. Inhibitors are an uncommon complication of mild haemophilia which frequently persist and may be associated with severe, life-threatening, haemorrhage. Forty-one percent of treated haemophilic family members had a history of factor VIII inhibitors, suggesting a familial predisposition to develop inhibitors in these kindreds. Sixteen patients from 11 families were genotyped. Seven different missense mutations affecting the light chain were detected and two in the A2 domain. Five patients from three families had a mutation causing a substitution of Trp2229 by Cys in the C2 domain which appears to predispose to inhibitor formation since 7 of the 18 affected individuals have a history of inhibitor development.

Mutation analysis and genetic service: the construction and use of national confidential databases of mutations and pedigrees.

The development of rapid mutation screening procedures allows the detection of mutations in large populations. This is particularly useful for inherited diseases of high mutational heterogeneity, such as haemophilia A and B, because the analysis of the very many different natural mutants clearly defines the features that are important to the function of the relevant gene and gene product. Furthermore, the characterization of the mutation in an index person from each affected family may lead to the construction of confidential databases of mutations and pedigrees that allow optimization of genetic service. We report how, motivated by the aforementioned concepts, we have planned and introduced in the UK a national strategy to optimize genetic service in both haemophilias and, in particular, we describe the principles that have guided us.

Detection of mutations in hemophilia a patients by chemical cleavage of mismatch method.

Hemophilia A is an X-linked disorder that leads to a defect in blood coagulation. This is caused by mutations in the factor VIII gene, which results in its activity being reduced or abolished in the blood-clotting cascade. The factor VIII gene is 186 kb long with 26 exons, varying from 69 bp (exon 5) to 3106 bp (exon 14) (1). The factor VIII mRNA is 9028 bases in length with a 7053 nucleotides long coding region (2).

Double contrast preparations: an in vitro study of some antifoaming agents.

An apparatus is described for the study of foam formation in double contrast preparations in vitro. Antifoaming agents are shown to be of considerable benefit to the double contrast technique, silicone and silicone-free antifoamers being equally effective. Silicone antifoamers are preferred because of their wide clinical acceptability. Antifoamer formulation and concentration are found to be critical factors in determining efficacy of foam suppression, and may lead to erroneous results in the clinic.

Cranio-maxillary fixation using supra-orbital pins.

This paper compares the forces which external frames, used for cranio-maxillary fixation, can resist. Clinically, several frames using supra-orbital pins have been proven satisfactory. By quantifying the resistance forces, a more objective assessment of their effectiveness is made. The resistance to backward displacement of the maxilla is measured and compared for 3 frames. Two frames are used for comparison of resistance to occlusal forces.

A problem with modern dental materials.

It may come as a surprise to learn that there is more than one discipline in medicine dealing with artificial organs. The obvious one is bio-engineering, which is largely concerned with fashioning existing biologically acceptable materials into useful spare parts such as hip or knee joints. The materials themselves hardly change, and the difference between rival prostheses lies more in design than novel chemistry. This is the world of titanium or cobalt-chromium joint designs, bone screws and plates, orthotic limbs, supports and wheelchairs, and futuristic ideas such as miniature video cameras for artificial eyes.

Review of tsetse flies and trypanosomosis in South Africa.

The history of tsetse flies and nagana (trypanosomosis) in South Africa, and especially in Zululand, is reviewed. Four valid tsetse fly species have been recorded from South Africa. Glossina morsitans morsitans disappeared from the most northerly parts of South Africa during the rinderpest epizootic between 1896-1897. Of the three remaining species that occurred in Zululand, now part of KwaZuluNatal Province, G. pallidipes was the most common vector of nagana in cattle, but was eradicated from this area in 1954. G. brevipalpis and G. austeni remained but were responsible for only a few sporadic cases of nagana up until 1990. A widespread outbreak occurred in 1990 where cattle served by 61 diptanks were found infected with Trypanosoma congolense and T. vivax. Dipping of cattle in a pyrethroid plus the therapeutic treatment of infected animals brought the disease under control. The outbreak also led to a trial to control G. brevipalpis from the most northerly parts of the Hluhluwe/Umfolozi Game Reserve making use of target technology as for savannah species. The results were not satisfactory and the trial was discontinued until further research could provide a more appropriate system for the control of this species. A Tsetse Research Station was established at Hellsgate near St. Lucia Lake where research on G. brevipalpis and G. austeni is conducted into ways and means of monitoring and controlling these species.

Parasites of domestic and wild animals in South Africa. XXXIII. Ixodid ticks on scrub hares in the north-eastern regions of northern and eastern Transvaal and of KwaZulu-Natal.

Ixodid ticks were collected from scrub hares (Lepus saxatilis) at three localities. Nine tick species were recovered from 24 hares examined at Pafuri, Kruger National Park, Northern Transvaal. The most abundant and prevalent species were Hyalomma truncatum, Rhipicephalus kochi and a Rhipicephalus species (near R. pravus). Twelve tick species were collected from 120 scrub hares examined around Skukuza, Kruger National Park, Eastern Transvaal. The immature stages of Hyalomma truncatum were most abundant and those of Amblyomma hebraeum most prevalent on the hares. No haematozoa were found on blood smears made from these hares. Thirty-four scrub hares on mixed cattle and game farms near Hluhluwe, north-eastern KwaZulu-Natal harboured 12 tick species. The most abundant and prevalent of these were the immature stages of Rhipicephalus muehlensi. Piroplasms, tentatively identified as Babesia leporis, were present on blood smears of eight of these hares. The host status of scrub hares for 18 ixodid tick species or subspecies found in South Africa is tabulated.