Sero-prevalence to hepatitis B and C virus infection in refugees from Mozambique in southern Africa

Serological markers for evidence of past exposure to hepatitis B virus (HBV) and hepatitis C virus (HCV) were investigated in a cohort of refugees from Mozambique. Serological markers for past exposure to HBV were detected in 56% of the population and, in addition, 13.2% carried the HBV surface antigen. Anti-HCV antibodies could be confirmed in 3.2% of the population and occurred mostly in the older individuals. Only one anti-HCV antibody positive individual was positive for HBsAg. Immunity to rubellavirus had reached 85% by 11 years of age.

Serologic markers for hepatitis B virus and hepatitis A virus in Bushmen in West Caprivi, Namibia

A community based sero-epidemiological study was undertaken to determine the age specific prevalence rates of hepatitis A virus (HAV) and hepatitis B virus (HBV) infection in a band of Bushmen in the West Caprivi, Namibia. All children tested and all but two of the adults tested showed the presence of anti-HAV antibodies. Nineteen individuals (18%) were positive for HBsAg and 65 (61%) individuals had serologic evidence of past exposure to HBV infection.

Isolation and preliminary characterization of a caprine rotavirus

Five cytopathic rotavirus strains were isolated in MA104 cells from stool specimens of kids with diarrhoea. Pre-treatment of the virus with trypsin and incorporation of low levels of trypsin in the maintenance medium were important for the successful cultivation of the strains in these cells. The isolates were shown to be group A rotaviruses by antigenic reactivity with a group A monoclonal antibody. This was confirmed by the migration patterns of the viral RNA genome during polyacrylamide gel electrophoresis, which also confirmed that all five strains had an identical RNA electropherotype. Analysis with monoclonal antibodies to the subgroup-specific VP6 antigen showed that these strains carried the subgroup I epitope.

Astrovirus-like particles, adenoviruses and rotaviruses associated with diarrhoea in piglets

Faecal specimens from 1- to 7-week-old piglets (n = 251) with acute diarrhoeal illness were examined by direct negative staining electron microscopy for the presence of viral agents. Rotaviruses were observed in almost 40% of cases while adenoviruses and astroviruses were also observed in 3 specimens each. The majority of the rotaviruses reacted with a commercial Group A rotavirus ELISA although in 11 specimens they did not react with the Group A antigen and could represent atypical rotaviruses. This is the first report of adenoviruses and astroviruses in diarrhoeal faecal specimens from pigs in South Africa.

Granular corneal dystrophy. Visual results and pattern of recurrence after lamellar or penetrating keratoplasty

BACKGROUND

Granular corneal dystrophy is a rare indication for corneal transplantation. Both penetrating and lamellar keratoplasty have been recommended, but because granular corneal dystrophy is known to recur within the donor material and multiple grafts may be necessary, the best surgical option has not been clearly established. The cellular cause of the dystrophy is unknown and the authors hypothesized that the rate and pattern of recurrence within lamellar and penetrating grafts might give clues to its etiology.

METHODS

The authors compared the visual outcome, rate, and pattern of recurrence after 20 penetrating keratoplasties and 11 lamellar keratoplasties for granular corneal dystrophy.

RESULTS

Penetrating keratoplasty and lamellar keratoplasty have a good visual outcome in granular corneal dystrophy. Visual acuities after both procedures were not statistically different. Recurrence of the dystrophy within the graft material was almost universal within 4 years. It first appeared centrally and superficially, occasionally adopting a vortex pattern suggesting epithelial involvement. The recurrence-free interval was independent of size and type of graft performed.

CONCLUSION

The authors recommend lamellar keratoplasty as a primary procedure in managing visually disabling granular corneal dystrophy if the deposits are limited to the superficial cornea. This is particularly applicable in younger patients in whom multiple procedures may be necessary over a lifetime due to recurrence of the dystrophy, and the lower morbidity rate associated with lamellar keratoplasty becomes appreciable. Although granular corneal dystrophy generally is classified as a stromal dystrophy, the pattern of recurrence is more consistent with an epithelial or tear-borne abnormality than a disease of the stromal keratocyte.

Low prevalence of human T lymphotropic virus type I in !Kung San in Bushmanland, Namibia

Antibodies to human immunodeficiency virus 1 (HIV-1) and human T lymphotropic virus type 1 (HTLV-I) have been identified in various population groups living in southern and central Africa. Sera from 291 !Kung Bushmen in Bushmanland, Namibia were examined for the presence of antibodies to HIV-1 and HIV-2 and to HTLV-I. Initial screening for HIV-1/2 by two enzyme-linked immunosorbent assays (ELISAs) revealed evidence of past exposure in four individuals. However, no HIV-1/2 infection could be confirmed by a particle agglutination assay, a recombinant ELISA, or by Western blot for HIV-1 and HIV-2. Indeterminate Western blot profiles (with a p55 for each and either a p25 or p18 band) existed for all four HIV-1-reactive sera. Eight sera were reactive in the HTLV-I ELISA, although only five were positive on a second ELISA. Only three of the five HTLV-I-reactive sera could be confirmed by Western blot.

Rotavirus in Saanen goats

Rotavirus particles were detected in the stools of 8 out of 12 Saanen kids with either diarrhoea or an increased rectal temperature. No other pathogenic organisms could be recovered from these kids. This is believed to be the first report of rotavirus infection in goats in southern Africa.

The effect of recurrent pterygium on corneal topography

Pterygium is known to cause corneal topographic changes that can result in decreased visual acuity. We present a case of recurrent pterygium causing blurred vision and diplopia, and document the corneal topographic changes, showing astigmatism of 15 diopters induced by lateral gaze, prior to surgical excision.

A comparison of the VP7 gene sequences of human and bovine rotaviruses

The sequences of the gene encoding VP7 (the major outer capsid protein) from one bovine and three human rotavirus strains were determined because of their unusual VP7 specificities. Two of the human strains (PA 169 and PA 151) had VP7 serotype 6 specificity whereas the two other strains, recovered from a child (HAL 1166) and a calf (678) belonged to VP7 serotype 8. The serotype 8 strains exhibited a high degree of sequence conservation when compared with each other and with other serotype 8 strains previously sequenced. The serotype 6 human strains shared a greater degree of sequence similarity with previously reported serotype 6 bovine strains than with other rotavirus serotypes; however the degree of sequence similarity among PA 169, PA 151 and the bovine strains was lower than had been previously reported for strains belonging to the same serotype. The demonstration of rotavirus serotypes that are shared between human and animal species supports the concept that interspecies transmission occurs and may play a role in rotavirus evolution.

Comparison of two rapid enzyme immunoassays with standard enzyme immunoassay and latex agglutination for the detection of human rotavirus in stools

We evaluated the performance of six commercially available immunoassays for their ability to detect rotaviruses in stool specimens. Four of the assays were enzyme-linked immunosorbent assays (ELISA), including two rapid enzyme immunoassays (Testpack, Abbott Laboratories, Chicago and Pinpoint, Cambridge Biomedical, UK), and the remaining two were latex agglutination tests. A total of 100 specimens from children with gastroenteritis were tested with the commercial immunoassays and compared with electron microscopy (EM) and polyacrylamide gel electrophoresis (PAGE) as reference tests for the detection of rotavirus. Discordant results were further evaluated by a standard blocking ELISA. The rapid EIAs were found to be highly sensitive (100% for the Testpack and 97% for the Pinpoint) and more sensitive than the other immunoassays tested. High specificity was also recorded with both rapid EIAs (96% and 100% for Testpack and Pinpoint, respectively). The rapid EIA tests were easy to perform, required no specialized equipment, and could yield a result in less than 15 min. The results show that each of the commercial assays evaluated could accurately detect rotavirus in the stools of children with gastroenteritis, although the suitability of choice of assay will ultimately depend upon the requirements of the individual laboratory.

Postoperative blunt trauma to 7.5 mm scleral pocket wounds

Two patients received blunt trauma to the operated eye after phacoemulsification cataract surgery. Both patients had a three-step 7.5 mm chord width, 3.0 mm long, curving incision, extending from sclera into clear cornea. One patient had rupture of the scleral tunnel and horizontal suture 20 days after surgery. The intraocular lens was dislocated into and along the scleral tunnel. The second patient had direct trauma four days after surgery, resulting in cheese-wiring of the horizontal nylon 10-0 suture and wound leakage but no other sequelae. Blunt trauma after scleral pocket phacoemulsification cataract surgery may result in clinical wound dehiscence if sufficient force is sustained.

Identification of a new VP4 serotype of human rotaviruses

A new VP4 gene allele was identified by sequencing of two rotavirus recovered from infants with diarrhea. Strains HAL1166 (a VP7 serotype 8 human rotavirus from Finland) and PA169 (a VP7 serotype 6 human rotavirus from Italy) present 22-43% nucleotide sequence divergence and 14-45% amino acid divergence in the VP4 gene with rotaviruses belonging to various VP4 gene alleles previously reported. Cross-neutralization analysis between PA169 and rotaviruses belonging to the other recognized VP4 (P) serotypes had previously shown that none of them was similar to PA169. Hyperimmune serum prepared against a reassortant with the VP4 gene of strain PA169 and the VP7 gene of serotype 2 strain DS1 failed to neutralize previously recognized human rotavirus VP4 serotypes, indicating that PA169 represents a new VP4 serotype specificity. In addition, one of four neutralizing monoclonal antibodies directed to the VP4 of PA169 was specific for this virus, while three others had very limited cross-reactivity with rotaviruses possessing different VP4s.

Straight needle corneal splinting for anterior segment surgery

Corneal splinting is an old and well established surgical technique and modern straight needles allow for atraumatic and accurate placement, providing an alternative to suture-fixation scleral ring support. We have routinely used two straight, 150-micrometer diameter, 16-millimeter length suture needles passed through clear cornea, to act as anterior segment splint supports during anterior segment surgery in which the cornea would otherwise collapse. The needles enter through the clear corneal periphery, pass across the anterior chamber, and exit through clear cornea in a criss-cross configuration. This splint technique is quick and easy to perform and is an alternative or addition to suture-fixation scleral ring support.

Prevalence of hepatitis B in !Kung (San) children from Bushmanland, Namibia

Serum samples from 248 predominantly !Kung children (aged 5-19 years) attending various bush schools and a clinic in Bushmanland, northern Namibia were examined for the presence of hepatitis B virus (HBV) markers by radioimmunoassay. HBsAg was detected in 18 (7.3%) children while 117 (47.6%) showed one or more markers of HBV infection. These prevalence rates are lower than those of the closely situated territory of Kavango to the north and East Caprivi to the north-east. No significant difference in HBs antigenaemia between !Kung boys and girls was found (p > 0.05). However, HBs antigenaemia was found to vary between children in different bush schools. A significantly higher number of children attending the Omatako bush school were positive for HBsAg than the number attending the Luhebu bush school (p < 0.0167). These local variations could assist in the initial targeting of HBV vaccine to high-risk areas. In situ investigations of hyperendemic foci in Bushmanland, Namibia should help to elucidate the variation in HBs antigenaemia and the factors responsible for transmission of HBV.

Molecular epidemiology and subgroup analysis of bovine group A rotaviruses associated with diarrhea in South African calves

Rotavirus-positive specimens were recovered from 143 Afrikander calves on two farms in the northeastern Cape of South Africa during late 1988 and 1989. The rotavirus strains were analyzed by polyacrylamide gel electrophoresis of the RNA genome, and four rotavirus RNA electrophoretypes, each with a long profile, were identified. A distinct RNA profile was identified on the farms during 1988, but by early 1989, two patterns existed, one unique to each farm. Over the next 8 months a new electrophoretic pattern emerged on one farm, whereas the pattern on the other farm remained unchanged. The rotavirus subgroup I antigen was detected in all specimens examined with subgroup-specific monoclonal antibodies. Non-group A rotaviruses were not identified by RNA genome analysis of 82 specimens from calves with diarrhea negative for group A rotaviruses by an enzyme-linked immunosorbent assay.

A comparison of low dose methotrexate bioavailability: oral solution, oral tablet, subcutaneous and intramuscular dosing

OBJECTIVE

To compare the relative bioavailability of low dose methotrexate (MTX) administered as tablet, oral solution, and subcutaneous (sc) injection to that of intramuscular (im) injection in patients with rheumatoid arthritis (RA).

METHODS

Twelve patients meeting the American College of Rheumatology criteria for RA had serial blood MTX concentration samples drawn over a 24-h period after receiving their normal weekly MTX dose. Relative bioavailability (F) of the tablet and oral solution formulations was determined by comparison of the area under the time-versus-serum-concentration curves (AUC) for the 2 different oral formulations as a percentage of the AUC for im injection. Also, relative bioavailability of the sc formulation was compared to im in 6 of the patients.

RESULTS

Mean F for the oral tablet was 0.85, while that for the oral solution was 0.87. Both oral formulations showed a statistically significant difference in mean F when compared to im (tablet vs im, p = 0.002, oral solution vs im, p = 0.009). No statistically significant difference, however, was found in mean relative bioavailability between tablet and solution (p = 0.744). The mean F for sc was 0.97; no statistically significant difference existed between the mean F values for the sc and im routes of administration (p = 0.657).

CONCLUSIONS

Our data suggest the oral solution may be substituted for tablet dosing and sc injection substituted for im. Thus, a variety of different dosing methodologies may be considered providing the most appropriate route in each patient, given issues of compliance, medication cost, and preference.

Excimer laser photorefractive keratectomy for myopia: 12 month follow-up

A prospective study of excimer laser photorefractive keratectomy was performed with the aim of correcting a range of myopic errors between -1.00 and -10.00 dioptres. Corneal healing was monitored through the first post-operative year by serial assessments of refraction, contrast sensitivity, corneal haze, pachymetry and keratometry. Eighty-one patients were recruited for the study. At 12 months 81% were within +/- 1.00 dioptre of desired emmetropia and with unaided vision of 6/12. Contrast sensitivity was found by Pelli-Robson assessment to be reduced throughout the 12 months and regression analysis predicted recovery by 2 years. At 12 months, however, only 15% of patients were found to have lost a single line of best corrected Snellen acuity. Predictability of results was found to be greatest for initial errors less than -4.00 dioptres. No serious complications were observed during the follow-up period, but refraction had not stabilised in all cases and patients remain under review.

Conjunctival autografting in the surgical management of pterygium

In a retrospective survey of 117 operations for primary or recurrent pterygium, conjunctival autografting was compared with both excision without conjunctival closure ('bare sclera excision') and excision with complete conjunctival closure. The probability of corneal recurrence at 36 months after surgery was determined by survival curve analysis. In previously unoperated cases conjunctival autografting (n = 15) resulted in a 14% probability of recurrence, compared with 70% for bare sclera excision (n = 50) and 69% for excision with complete conjunctival closure (n = 20). In previously operated cases conjunctival autografting (n = 17) resulted in a 7% probability of recurrence, compared with 82% for bare sclera excision (n = 15). Hazard ratio analysis confirmed the statistical significance of these results at the 95% confidence level. Conjunctival autografting was more likely to produce an improvement in visual acuity than other forms of surgery.

Indications, results, and complications of refractive corneal surgery with lasers

Large numbers of patients are being treated for myopia, hyperopia, and astigmatism using the excimer laser. For many patients who are treated for myopia and hyperopia, the procedure is elective and these treatments remain investigational. The use of other lasers for refractive surgery is at an earlier stage, with human trials commencing for infrared lasers. Animal studies are being performed for pulsed picosecond and solid-state ultraviolet lasers. The indications for refractive treatment should be clearly defined, although the results of laser application remain the subject of investigation. Complications of laser application to the cornea occur in the immediate, short-term, and long-term posttreatment period. A continual improvement in refractive results along with a reduction in complications remains the goal of laser refractive research.

Relative frequency of VP4 gene alleles among human rotaviruses recovered over a 10-year period (1982-1991) from Japanese children with diarrhea

The relative frequencies of the Wa (corresponding to serotype P1A), DS-1(P1B), M37(P2), and AU-1(P3) alleles of the VP4 gene from rotaviruses collected from the stools of individuals in Japan between 1982 and 1991 were determined to be 83.1, 15.6, 0, and 1.3%, respectively, by a polymerase chain reaction-based typing assay.

Distribution of VP4 gene alleles in human rotaviruses by using probes to the hyperdivergent region of the VP4 gene

The rotavirus VP4 protein elicits the production of neutralizing antibodies and is known to play a role in inducing resistance to disease. At least five human rotavirus VP4 gene alleles have been described on the basis of antigenic polymorphism and/or nucleotide sequence differences. In the present study, we developed cDNA probes directed at the hyperdivergent region of the VP4 gene of the five described human rotavirus VP4 alleles (Wa, DS1, M37, AU228, and 69M) and used them in hybridization assays with human rotavirus strains from Latin America and Europe to determine the distribution of the VP4 gene alleles in nature. The Wa-like allele was detected most frequently, occurring in 57% of the 402 rotavirus strains tested, and the DS1-like allele was the next most common, occurring in 14% of the strains tested. The M37- and AU228-like alleles were detected in only 4 and 3% of the rotavirus strains tested, respectively, whereas the 69M-like VP4 gene allele was not detected. Several rotavirus strains from Europe did not react with any of the VP4 gene probes, although they did hybridize to a probe generated from a representative strain from the group. These data indicate the global distribution of various VP4 gene alleles and raise the possibility that other, unrecognized human VP4 alleles exist in nature because almost one-fourth of the strains could not be classified into any of the established VP4 groups.