Prevalence and Distribution of Cryptosporidium spp. and Giardia lamblia in Rural and Urban Communities of South Africa

OBJECTIVE

Enteric diseases remain a serious health problem globally. High prevalence is evident in regions with poor socioeconomic conditions, poor sanitation, and inadequate clean water supply, such as South Africa. Designing an effective strategy, however, requires local knowledge, which can be particularly challenging to acquire in low-and middle-income countries. As the first step in this process, we investigated the prevalence and distribution of protozoan parasites Cryptosporidium and Giardia in the rural and urban gastrointestinal clinics of South Africa.

METHODS

A cross-sectional study was conducted to assess the prevalence of enteric parasites Cryptosporidium and G. lamblia in rural and urban communities of South Africa. Stool samples were collected from November 2013 to June 2015 from patients with diarrhea (n=227) and without diarrhea (n=257). DNA was extracted and a diagnostic Taqman qPCR assay was performed to detect these protozoan parasites, which was further confirmed by the Sanger sequencing of a few samples.

RESULTS

Of the 484 stool specimens collected, 34% (166/484) were positive for either Cryptosporidium spp. or Giardia lamblia parasites, with only 5% containing both parasites (22/484). In both study populations, Cryptosporidium was the most prevalent parasite (overall 25%) followed by Giardia (19%).

CONCLUSION

This study discovered that both Giardia and Cryptosporidium parasites might contribute to diarrheal disease in South Africa and are more prevalent in rural communities. Future studies are needed to identify the source of the infection and design appropriate interventions to reduce the burden of the disease.

AMAÇ

Enterik hastalıklar küresel olarak ciddi bir sağlık sorunu olmaya devam etmektedir. Güney Afrika gibi düşük sosyo-ekonomik koşulların, kötü sanitasyonun ve yetersiz temiz su kaynaklarının olduğu bölgelerde yüksek prevalans görülmektedir. Ancak etkili bir strateji tasarlamak için, düşük ve orta gelirli ülkelerde edinilmesi özellikle zor olabilecek yerel bir bilgi gerektirmektedir. Bu süreçte biz ilk adım olarak, Güney Afrika’nın kırsal ve kentsel gastrointestinal kliniklerinde protozoan parazitler Cryptosporidium ve Giardia’nın prevalansını ve dağılımını araştırdık.

YÖNTEMLER

Güney Afrika’nın kırsal ve kentsel topluluklarında Cryptosporidium ve G. lamblia enterik parazitlerinin sıklığını araştırmak için kesitsel bir çalışma yapıldı. İshali olan (n=227) ve olmayan (n=257) hastaların Kasım 2013-Haziran 2015 tarihleri arasında dışkı örnekleri toplandı. DNA ekstrakte edildi ve bu protozoan parazitleri saptamak için tanısal bir Taqman qPCR tahlili kullanılarak, birkaç örnek Sanger dizilimi ile daha da doğrulandı.

BULGULAR

Toplanan 484 dışkı örneğinin %34’ü (166/484) Cryptosporidium spp. veya Giardia lamblia parazitleri için pozitifti ve örneklerin sadece %5’i her iki paraziti de içeriyordu (22/484). Her iki çalışma popülasyonunda da Cryptosporidium en yaygın parazitti (toplam %25) ve bunu Giardia (%19) izledi.

SONUÇ

Bu çalışma, hem Giardia hem de Cryptosporidium parazitlerinin Güney Afrika’daki ishal hastalığına katkıda bulunabileceğini ve kırsal topluluklarda daha yaygın olduğunu göstermiştir. Hem enfeksiyonun kaynağını belirlemek hem de hastalığın yükünü azaltmak için uygun müdahaleleri tasarlamak için gelecekteki çalışmalara ihtiyaç vardır.

Molecular diversity of Giardia duodenalis in children under 5 years from the Manhiça district, Southern Mozambique enrolled in a matched case-control study on the aetiology of diarrhoea

Giardia duodenalis is an enteric parasite commonly detected in children. Exposure to this organism may lead to asymptomatic or symptomatic infection. Additionally, early-life infections by this protozoan have been associated with impaired growth and cognitive function in poor resource settings. The Global Enteric Multicenter Study (GEMS) in Mozambique demonstrated that G. duodenalis was more frequent among controls than in diarrhoeal cases (≥3 loosing stools in the previous 24 hours). However, no molecular investigation was conducted to ascertain the molecular variability of the parasite. Therefore, we describe here the frequency and genetic diversity of G. duodenalis infections in children younger than five years of age with and without diarrhoea from the Manhiça district in southern Mozambique enrolled in the context of GEMS. Genomic DNA from 757 G. duodenalis-positive stool samples by immunoassay collected between 2007-2012, were reanalysed by multiplex PCR targeting the E1-HP and C1-P21 genes for the differentiation of assemblages A and B. Overall, 47% (353) of the samples were successfully amplified in at least one locus. Assemblage B accounted for 90% (319/353) of all positives, followed by assemblage A (8%, 29/353) and mixed A+B infections (1%, 5/353). No association between the presence of a given assemblage and the occurrence of diarrhoea could be demonstrated. A total of 351 samples were further analysed by a multi-locus sequence genotyping (MLSG) approach at the glutamate dehydrogenase (gdh), ß-giardin (bg) and triose phosphate isomerase (tpi) genes. Overall, 63% (222/351) of samples were genotyped and/or sub-genotyped in at least one of the three markers. Sequence analysis revealed the presence of assemblages A (10%; 23/222) and B (90%; 199/222) with high molecular diversity at the nucleotide level within the latter; no mixed infections were identified under the MLSG scheme. Assemblage A sequences were assigned to sub-assemblages AI (0.5%, 1/222), AII (7%, 15/222) or ambiguous AII/AIII (3%, 7/222). Within assemblage B, sequences were assigned to sub-assemblages BIII (13%, 28/222), BIV (14%, 31/222) and ambiguous BIII/BIV (59%, 132/222). BIII/BIV sequences accumulated the majority of the single nucleotide polymorphisms detected, particularly in the form of double peaks at chromatogram inspection. This study demonstrated that the occurrence of gastrointestinal illness (diarrhoea) was not associated to a given genotype of G. duodenalis in Mozambican children younger than five years of age. The assemblage B of the parasite was responsible for nine out of ten infections detected in this paediatric population. The extremely high genetic diversity observed within assemblage B isolates was compatible with an hyperendemic epidemiological scenario where infections and reinfections were common. The obtained molecular data may be indicative of high coinfection rates by different G. duodenalis assemblages/sub-assemblages and/or genetic recombination events, although the exact contribution of both mechanisms to the genetic diversity of the parasite remains unknown.

Gut microbiome communication with bone marrow regulates susceptibility to amebiasis

The microbiome provides resistance to infection. However, the underlying mechanisms are poorly understood. We demonstrate that colonization with the intestinal bacterium Clostridium scindens protects from Entamoeba histolytica colitis via innate immunity. Introduction of C. scindens into the gut microbiota epigenetically altered and expanded bone marrow granulocyte-monocyte progenitors (GMPs) and resulted in increased intestinal neutrophils with subsequent challenge with E. histolytica. Introduction of C. scindens alone was sufficient to expand GMPs in gnotobiotic mice. Adoptive transfer of bone marrow from C. scindens-colonized mice into naive mice protected against amebic colitis and increased intestinal neutrophils. Children without E. histolytica diarrhea also had a higher abundance of Lachnoclostridia. Lachnoclostridia C. scindens can metabolize the bile salt cholate, so we measured deoxycholate and discovered that it was increased in the sera of C. scindens-colonized specific pathogen-free and gnotobiotic mice, as well as in children protected from amebiasis. Administration of deoxycholate alone increased GMPs and provided protection from amebiasis. We elucidated a mechanism by which C. scindens and the microbially metabolized bile salt deoxycholic acid alter hematopoietic precursors and provide innate protection from later infection with E. histolytica.

Case-Control Study of Cryptosporidium Transmission in Bangladeshi Households

Background

Cryptosporidium is a leading contributor to diarrheal morbidity and mortality in under-5 children worldwide. As there is no vaccine and no effective drug therapy in young children for this infection, preventing infection is critical. We undertook a pilot case-control study to define the extent of person-to-person transmission of cryptosporidiosis within an urban and a rural community in Bangladesh.

Methods

We enrolled 48 case families with a Cryptosporidium-infected child aged 6–18 months. Controls were age- and sex-matched Cryptosporidium-negative children in 12 households. Children and household members were followed for 8 weeks with weekly illness survey and stool testing with quantitative polymerase chain reaction for Cryptosporidium.

Results

In the 24 urban case families, the secondary attack rate was 35.8% (19/53) vs 0% (0/11) in controls (P = .018, χ² test). In contrast, in the 24 rural case families, the secondary attack rate was 7.8% (5/64) vs 0% (0/21) in controls (P = .19, χ² test). Genotyping by gp60 demonstrated infection with the same subspecies in 5 families, and evidence of transmission in 2. Serologic response to Cryptosporidium infection was associated with younger age, longer duration of infection, and Cryptosporidium hominis gp60_IbA9G3R2 infection.

Conclusions

In the urban site, the high rate of secondary infection and infection with the same subspecies within families suggests that person-to-person transmission is a major source of Cryptosporidium infection for young children living in this region. Molecular genotyping can be applied to determine transmission of Cryptosporidium in endemic regions. Further work is needed to understand the differences in parasite transmissibility and immunity to different genotypes.

Entamoeba Species in South Africa: Correlations With the Host Microbiome, Parasite Burdens, and First Description of Entamoeba bangladeshi Outside of Asia

Background

Diarrhea is frequent in communities without clean water, which include low-income South African populations in Giyani and Pretoria. In these populations, the amount of diarrhea caused by Entamoeba histolytica, inclusive of all ages, sexes, and human immunodeficiency virus status, is uncertain. Infection with E. histolytica can modulate the host microbiota, and a key species indicative of this is the Prevotella copri pathobiont.

Methods

A cross-sectional study of patients attending gastroenterology clinics was conducted to determine the frequency and burden of 4 Entamoeba species and P. copri.

Results

Entamoeba species were present in 27% of patients (129/484), with E. histolytica detected in 8.5% (41), E. dispar in 8% (38), E. bangladeshi in 4.75% (23), and E. moshkovskii in 0%. This is the first description of E. bangladeshi outside Bangladesh. In E. histolytica-positive samples, the levels of both the parasite and P. copri were lower in nondiarrheal samples, validating the results of a study in Bangladesh (P = .0034). By contrast, in E. histolytica-negative samples positive for either of the nonpathogenic species E. dispar or E. bangladeshi, neither P. copri nor Entamoeba levels were linked to gastrointestinal status.

Conclusions

Nonmorphologic identification of this parasite is essential. In South Africa, 3 morphologically identical Entamoeba were common, but only E. histolytica was linked to both disease and changes in the microbiota.

Vitamin D supplementation during pregnancy and infancy reduces aeroallergen sensitization: a randomized controlled trial

BACKGROUND

Vitamin D has immune-modulating effects. We determined whether vitamin D supplementation during pregnancy and infancy prevents aeroallergen sensitization and primary care respiratory illness presentations.

METHODS

A randomized, double-blind, placebo-controlled parallel-group trial. We assigned pregnant women, from 27-week gestation to birth, and then their infants, from birth to 6 months, to placebo or one of two dosages of daily oral vitamin D. Woman/infant pairs were randomized to: placebo/placebo, 1000 IU/400 IU or 2000 IU/800 IU. When the children were 18 months old, we measured serum-specific IgE antibodies and identified acute primary care visits described by the doctor to be due to a cold, otitis media, an upper respiratory infection, croup, asthma, bronchitis, bronchiolitis, a wheezy lower respiratory infection or fever and cough.

RESULTS

Specific IgE was measured on 185 of 260 (71%) enrolled children. The proportion of children sensitized differed by study group for four mite antigens: Dermatophagoides farinae (Der-f1, Der-f2) and Dermatophagoides pteronyssinus (Der-p1, Der-p2). With results presented for placebo, lower dose, and higher dose vitamin D, respectively (all P < 0.05): Der-f1 (18%, 10%, 2%), Der-f2 (14%, 3%, 2%), Der-p1 (19%, 14%, 3%) and Der-p2 (12%, 2%, 3%). There were study group differences in the proportion of children with primary care visits described by the doctor as being for asthma (11%, 0%, 4%, P = 0.002), but not for the other respiratory diagnoses.

CONCLUSIONS

Vitamin D supplementation during pregnancy and infancy reduces the proportion of children sensitized to mites at age 18 months. Preliminary data indicate a possible effect on primary care visits where asthma is diagnosed.

Natural History of Cryptosporidiosis in a Longitudinal Study of Slum-Dwelling Bangladeshi Children: Association with Severe Malnutrition

Background

Cryptosporidiosis is a common cause of infectious diarrhea in young children worldwide, and is a significant contributor to under-five mortality. Current treatment options are limited in young children. In this study, we describe the natural history of Cryptosporidium spp. infection in a birth cohort of children in Bangladesh and evaluate for association with malnutrition.

Methodology/Principal Findings

This is a longitudinal birth cohort study of 392 slum-dwelling Bangladeshi children followed over the first two years of life from 2008 to 2014. Children were monitored for diarrheal disease, and stool was tested for intestinal protozoa. Anthropometric measurements were taken at 3-month intervals. A subset of Cryptosporidium positive stools were genotyped for species and revealed that C. hominis was isolated from over 90% of samples. In the first two years of life, 77% of children experienced at least one infection with Cryptosporidium spp. Non-diarrheal infection (67%) was more common than diarrheal infection (6.3%) although 27% of children had both types of infection. Extreme poverty was associated with higher rates of infection (chi-square, 49.7% vs 33.3%, p = 0.006). Malnutrition was common in this cohort, 56% of children had stunted growth by age two. Children with Cryptosporidium spp. infection had a greater than 2-fold increased risk of severe stunting at age two compared to uninfected children (odds ratio 2.69, 95% CI 1.17, 6.15, p = 0.019) independent of sex, income, maternal body-mass index, maternal education and weight for age adjusted z (WAZ) score at birth.

Conclusions/Significance

Cryptosporidium infection is common (77%) in this cohort of slum-dwelling Bangladeshi children, and both non-diarrheal and diarrheal infections are significantly associated with a child’s growth at 2 years of age.

Diarrheal disease is a leading cause of death in young children worldwide. Cryptosporidium species are responsible for a large proportion of global burden of diarrhea. This study describes the natural history of cryptosporidiosis in a birth cohort of impoverished Bangladeshi children. Children were enrolled at birth and monitored for diarrhea twice a week for two years. Stool samples were tested for enteric protozoa. Children in this cohort had significant rates of malnutrition compared to the W.H.O. reference population, and extreme poverty was common. A majority of children were infected with Cryptosporidium spp, and we found that children who had at least one infection with Cryptosporidium spp during the two year follow up period were significantly more likely to have growth faltering by age 24 months. Cryptosporidiosis is a common infection in this cohort, and is associated with poverty and reduced growth during the first two years of life.

Resistance to intestinal Entamoeba histolytica infection is conferred by innate immunity and Gr-1+ cells

Establishment of intestinal infection with Entamoeba histolytica depends on the mouse strain; C57BL/6 mice are highly resistant, and C3H/HeJ mice are relatively susceptible. We found that resistance to intestinal infection was independent of lymphocyte activity or H-2 haplotype and occurred in the first hours to days postchallenge according to in vivo imaging. At 18 h postchallenge, the ceca of resistant C57BL/6 mice were histologically unremarkable, in contrast to the severe inflammation observed in susceptible C3H/HeJ mice. Comparison of cecal gene expression in C3H/HeJ and C57BL/6 mice demonstrated that there was parasite-induced upregulation of proinflammatory and neutrophil chemotaxis transcripts and there was downregulation of transforming growth factor beta signaling molecules. Pretreatment with dexamethasone abrogated the partial resistance of C3H/HeJ or CBA mice through an innate, lymphocyte-independent mechanism, but it had no effect on the high-level resistance of C57BL/6 mice. Similarly, administration of a neutrophil-depleting anti-Gr-1 monoclonal antibody (RB6-8C5) decreased the partial resistance of CBA mice and led to severe pathology compared to control antibody-treated mice, but it had no effect on C57BL/6 resistance. These data indicate that there are discrete mechanisms of innate resistance to E. histolytica depending on the host background and, in contrast to other reports, imply that neutrophils are protective and not damaging in intestinal amebiasis.

The genome of the protist parasite Entamoeba histolytica

Entamoeba histolytica is an intestinal parasite and the causative agent of amoebiasis, which is a significant source of morbidity and mortality in developing countries. Here we present the genome of E. histolytica, which reveals a variety of metabolic adaptations shared with two other amitochondrial protist pathogens: Giardia lamblia and Trichomonas vaginalis. These adaptations include reduction or elimination of most mitochondrial metabolic pathways and the use of oxidative stress enzymes generally associated with anaerobic prokaryotes. Phylogenomic analysis identifies evidence for lateral gene transfer of bacterial genes into the E. histolytica genome, the effects of which centre on expanding aspects of E. histolytica's metabolic repertoire. The presence of these genes and the potential for novel metabolic pathways in E. histolytica may allow for the development of new chemotherapeutic agents. The genome encodes a large number of novel receptor kinases and contains expansions of a variety of gene families, including those associated with virulence. Additional genome features include an abundance of tandemly repeated transfer-RNA-containing arrays, which may have a structural function in the genome. Analysis of the genome provides new insights into the workings and genome evolution of a major human pathogen.

Bone mineral density in relation to medical and lifestyle risk factors for osteoporosis in premenopausal, menopausal and postmenopausal women in general practice

BACKGROUND

Interest in the prevention of osteoporosis is increasing and thus there is a need for an acceptable osteoporosis prevention programme in general practice.

AIM

A study was undertaken to identify a cohort of middle-aged women attending a general practice who would be eligible for a longitudinal study looking at bone mineral density, osteoporosis and the effectiveness of hormone replacement therapy. This study aimed to describe the relationship between medical and lifestyle risk factors for osteoporosis and the initial bone density measurements in this group of women.

METHOD

A health visitor administered a questionnaire to women aged between 48 and 52 years registered with a Belfast general practice. The main outcome measures were menopausal status, presence of medical and lifestyle risk factors and bone mineral density measurements.

RESULTS

A total of 358 women our of 472 (76%) took part in the study which was conducted in 1991 and 1992. A highly significant difference was found between the mean bone mineral density of premenopausal, menopausal and postmenopausal women within the narrow study age range, postmenopausal women having the lowest bone mineral density. A significant relationship was found between body mass index and bone mineral density, a greater bone mineral density being found among women with a higher body mass index. Risk factors such as smoking and sedentary lifestyle were common (reported by approximately one third of respondents) but a poor relationship was found between these two and all the other risk factors and bone mineral density in this age group.

CONCLUSION

Risk of osteoporosis cannot be identified by the presence of risk factors in women aged between 48 and 52 years. In terms of a current prevention strategy for general practice it would be better to take a population-based approach except for those women known to be at high risk of osteoporosis: women with early menopause or those who have had an oophorectomy.

Infrequent detection of Chlamydia trachomatis in a longitudinal study of women with treated cervical infection

OBJECTIVE

To determine how often Chlamydia trachomatis cervical infections are detected in women following completion of a currently recommended treatment regimen and the reason for recurrence.

METHODS

A longitudinal follow-up study of 43 initially C trachomatis-positive women for periods of up to two years.

RESULTS

C trachomatis was detected in three women, 19, 16 and about four months, respectively after completion of treatment. All specimens from the other 40 women which were taken during visits two to seven, that is periods of three to 700 days after treatment, were chlamydia-negative.

CONCLUSION

Although C trachomatis is usually eradicated from the genital tract by conventional treatment, occasionally it may be found again. It is difficult to determine whether detection after treatment is due to persistence or reinfection and further studies are required.

A longitudinal study of pelvic inflammatory disease

OBJECTIVE

To study the microbiology and long term prognosis of pelvic inflammatory disease (PID).

DESIGN

A prospective study of women with laparoscopically confirmed PID.

SETTING

Teaching hospital in central London.

SUBJECTS

23 women with PID.

OUTCOME MEASURES

Microbiological investigations at the time of diagnosis and at follow up; subsequent fertility and the occurrence of pelvic pain.

RESULTS

PID diagnosed by laparoscopy was regarded as moderate to severe in 15 cases. Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum or a combination of these micro-organisms were detected most frequently in the cervix, less often in the endometrium and least in the tubes, C. trachomatis being the micro-organism found most commonly in the tubes. There was serological evidence of acute chlamydial infection in 13 of 20 cases in which paired sera were available and a serological response to M. hominis in 9 of 12 cases in which it was possible to evaluate the results. On the basis of microbiological and serological results, C. trachomatis appeared to be the most important aetiological agent in 10 cases, N. gonorrhoeae in four cases, M. hominis in three cases and U. urealyticum in none; in five cases, two of these micro-organisms appeared to be of equal importance. After 1 to 3 years, 33% of the women were having difficulty conceiving and 56% continued to complain of pelvic pain.

CONCLUSION

It is difficult to be certain of the infectious cause of PID in any given case. However, the evidence that N. gonorrhoeae and C. trachomatis are pathogens is very strong. M. hominis may be responsible for a few cases on its own or together with other micro-organisms.

A reappraisal of chlamydial and nonchlamydial acute non-gonococcal urethritis

A cohort of 112 men presenting with acute non-gonococcal urethritis (NGU) was investigated for the presence of Chlamydia trachomatis. Men with 3 or more episodes of NGU in the preceding 12 months, or who had received treatment for NGU in the preceding 3 months were excluded. C. trachomatis was sought by examination of urethral smears by direct immunofluorescence, and by examination of the centrifuged deposit from a first pass urine (FPU) sample by direct immunofluorescence, IDEIA, and the polymerase chain reaction. Urethral samples from 48 men were positive for CT, and the FPU samples from an additional 7 men were positive by at least 2 assays. With such intensive investigation it is likely that those men identified as chlamydia-negative were genuinely free from the infection. The clinical history and response to treatment of those men who were chlamydia-positive were compared with those of the chlamydia-negative men. They differed in that a larger proportion of the chlamydia-positive men reported having had intercourse with more than one partner in the previous 3 months, and having had fewer previous episodes of NGU. Moreover, in contrast to some previous studies, after one week of treatment with doxycycline, a larger proportion (65%) of the chlamydia-negative men than the chlamydia-positive men (40%) was cured, although the difference was not sustained following later treatment.

Detection of Chlamydia trachomatis by direct immunofluorescence improved by centrifugation of specimens

During a study of women with laparoscopically investigated pelvic pain, genital tract specimens were examined for Chlamydia trachomatis using a direct fluorescent antibody (DFA) technique (MicroTrak, Syva) and culture. Some smears, particularly those from the upper genital tract, contained an inadequate number of cells when examined by the DFA technique and many cell monolayers were destroyed by the specimens. To obtain results for such samples, or to confirm the original DFA result, additional specimens which had been frozen at -70 degrees C or in liquid nitrogen were centrifuged at high speed and the resulting deposit examined by the DFA technique. By this means, 32 negative results were confirmed for specimens from 10 chlamydia-negative patients with pelvic inflammatory disease or with high chlamydial antibody titres, and 26 negative results were confirmed for 19 patients who were positive at other sites. In addition, three chlamydia-positive and six chlamydia-negative results were obtained for sites where the original smear for DFA testing had been inadequate (few epithelial cells) and six specimens that were negative originally were found to be positive. Thus, of 73 specimens that were either inadequate or negative by DFA testing originally, 9 (12%) were positive by DFA testing after centrifugation.

Simplification of procedures used to test urine samples for Chlamydia trachomatis

Two methods of simplifying the procedure for examining urine samples for Chlamydia trachomatis were investigated. When 73 urine samples from 56 men with acute non-gonococcal urethritis were examined by direct immunofluorescence (MicroTrak), centrifuging 1 ml volumes of urine at 13,000 rpm for five minutes was at least as efficient for detecting C trachomatis as centrifuging larger volumes at 3000 rpm for 30 minutes. Furthermore, examination of urine produced during a visit to a sexually transmitted disease clinic was at least as efficient as examination of early morning urine for detecting C trachomatis by MicroTrak, or by an enzyme immunoassay (IDEIA). Both modifications have practical advantages and should encourage the use of urine samples for diagnosing chlamydial infections in men.

The value of urine samples from men with non-gonococcal urethritis for the detection of Chlamydia trachomatis

Chlamydia trachomatis was sought at first and subsequent clinic visits in urethral swabs and urines from 112 heterosexual men with acute non-gonococcal urethritis (NGU). In comparison with a urethral swab tested by Micro Trak (MT), a urine deposit tested in the same way was 90% as sensitive. Examining a urine deposit by the enzyme immunoassay IDEIA was a little less sensitive (89%) than examining a similar deposit by MT, and was less sensitive (82%) than examining a urethral swab by MT. The results of testing urines were little influenced by collecting them either before or after swabbing the urethra, and there was evidence that examining all of a urine sample by IDEIA would have increased sensitivity. Overall, 55 (49%) of the men were diagnosed as C trachomatis-positive based on the results of testing both a urethral swab and a urine sample. Furthermore, a small numbers of chlamydiae were detected by examining urine by MT and, to a lesser extent, by IDEIA, so that there is no reason why this non-invasive approach should not be successful in men other than those with acute NGU.

Detection of Chlamydia trachomatis by the polymerase chain reaction in swabs and urine from men with non-gonococcal urethritis

A polymerase chain reaction (PCR) was developed for Chlamydia trachomatis in which a 380 base pair DNA fragment was amplified. Amplification occurred with the DNA from the 15 serovars but not with that from other Chlamydia spp or with DNA from a variety of other organisms. Chlamydial DNA (10(-16) g) could be detected and the PCR seemed to be able to detect single organisms. Urethral swabs were obtained from 37 men with acute non-gonococcal urethritis (NGU), 18 (49%) of whom were positive for C trachomatis by MicroTrak. As a result of clinical re-examinations 65 urethral swabs were available for analysis by the PCR. In comparison with MicroTrak, PCR had a sensitivity of 95%, a specificity of 94%, a positive predictive value of 86% and a negative predictive value of 98%. The PCR was apparently less sensitive (82%) in tests on urine samples. Overall, however, values of sensitivity and specificity of the PCR compared favourably with those of MicroTrak. The PCR for C trachomatis is likely to be a valuable technique for research, but problems of DNA contamination suggest that it should not be recommended for routine diagnosis.

Chlamydia trachomatis in the fallopian tubes of women without laparoscopic evidence of salpingitis

23 women with lower abdominal pain and Chlamydia trachomatis in the cervix, urethra, or both sites were studied. Laparoscopy was done with sampling of the endometrium and fallopian tubes for detection of C trachomatis. 11 women had laparoscopic evidence of pelvic inflammatory disease (PID); C trachomatis was detected in the upper genital tract of 8, but not in the upper tract of 5 who had laparoscopy again after treatment. The organism was also found in the upper genital tract of 9 of the 12 women without laparoscopic evidence of PID. Most of the women with abdominal pain or tenderness had tubal or endometrial C trachomatis infection, although only half had laparoscopic evidence of salpingitis. This finding suggests that antibiotic treatment should be given as soon as chlamydial infection is detected in the cervix and that pain does not necessarily point to C trachomatis in the upper genital tract. Laparoscopy may miss important pathogens in the upper genital tract, unless the procedure is complemented with detailed microbiological investigation.

Improved sensitivity of an enzyme immunoassay IDEIA for detecting Chlamydia trachomatis

In tests on 375 genital tract specimens a commercially available enzyme immunoassay for Chlamydia trachomatis (IDEIA; Boots-Celltech) was found to have sensitivity values of 62% for men and 74% for women, and a specificity of 97% for both groups, relative to the results obtained by a fluorescence assay (Micro Trak; Syva). The positive predictive value and the negative predictive value of the immunoassay were 91% and 87%, respectively. Collection of samples for IDEIA in transport medium in plastic phials, as opposed to glass phials recommended by the manufacturer, had no effect on these values. Tests of the sensitivity of IDEIA using laboratory strains of C trachomatis showed that the assay detected chlamydial elementary bodies only at dilutions at least 10-fold lower than those at which they could be detected by Micro Trak. Tests of the specificity of the assay with microorganisms found in the genital tract, other than chlamydiae, showed that reactions occurred with a number of these. Testing three cervical swabs from the same patient, with the material taken into a single phial of transport medium, increased the sensitivity of IDEIA from 74% to 96%, without reducing the specificity which remained at 97%. It is concluded that this approach enchances the value of the test in a sexually transmitted disease clinic population and may do so in a population with a low prevalence of chlamydiae.

Factors influencing the in-vitro sensitivity of Ureaplasma urealyticum to tetracyclines

The sensitivity of 23 strains of Ureaplasma urealyticum to doxycycline was measured by a metabolism-inhibition technique. The minimal inhibitory concentrations were not influenced by using, as inocula in the tests, organisms either directly from the patient or after culture, providing that the numbers of organisms in the inocula were about the same in both. All the strains were sensitive to doxycycline but an apparent increase in the resistance of the cultured organisms occurred when the number, expressed as colour-changing units (ccu), in the inoculum was 10(5) or more/ml. Tests may be undertaken on cultured organisms of U. urealyticum but it is recommended that a standard inoculum of 10(3)-10(4) ccu/ml should be used.

Infection of the epididymis by Ureaplasma urealyticum

Ureaplasma urealyticum organisms (ureaplasmas) were isolated from the urethra and epididymal aspirate of a man aged 24 who had acute right sided epididymitis. No other microorganisms were detected, and he had no chlamydial antibody response. A fourfold antibody response to the epididymal ureaplasma isolate was detected by two methods, however, and the patient responded clinically to doxycycline, to which the ureaplasmal isolates were susceptible in vitro. These findings suggest that U urealyticum had a causative role.

Lymphocyte abnormalities in Behçet's syndrome

In order to test indirectly the hypothesis that Behçet's syndrome is caused by a virus, lymphocytes from eighty-six patients were evaluated for two parameters consistent with persistent virus infection: chromosomal abnormalities and decreased ability to herpes simplex virus type I (HSV) to grow in lymphocyte cultures stimulated by PHA. Whereas HSV grew in lymphocytes cultured from all normal donors, replication was impaired in lymphocytes from 37% of the patients with Behçet's syndrome. This figure is increased to 57% if patients receiving steroids or cytotoxic drugs were excluded. Lymphocytes were scored as chromosomally abnormal from sixteen of the thirty-eight patients examined, compared with only one of seventeen normal controls. There was damage to specific chromosomes in four patients. The frequency with which chromosomal abnormalities were detected was significantly related to failure to replicate HSV and inversely related to concomitant steroid treatment. The findings are consistent with a viral aetiology for Behçet's syndrome but other explanations are not excluded.

Autoimmunity in chronic graft-versus-host disease

F₁ mice with chronic GVH disease were studied to investigate the hypothesis that non-specific stimulation of helper T cells, such as might be seen in graft-versus-host (GVH) disease, results in autoantibody production. Antinuclear antibody (ANA) was detected significantly more frequently in F₁ mice with GVH disease than in control animals. The antigenic specificities of the ANA indicate that it is of host origin and, since it reacts with syngeneic nuclei, it can be considered a true autoantibody. The pattern of development, intensity, prevalence and sex distribution of ANA reactions differed notably in experiments with A × CBA F₁s compared to those with C57B1/6 × BALB/c F₁s suggesting that these parameters of ANA formation are influenced significantly by the genotype of the animal with GVH disease.