Greater Rise In Titre Research Articles

SEROLOGICAL RESPONSE TO CANINE DISTEMPER VACCINATION IN WILD CAUGHT RACCOONS (PROCYON LOTOR).

Canine distemper virus (CDV) is a well-known RNA virus that affects domestic dogs and all families of wild terrestrial carnivores. Spillover infections from wildlife to domestic animals are mitigated by preventive vaccination, but there is limited information on the off-label use of veterinary vaccines for wildlife like raccoons (Procyon lotor). Twenty wild-caught raccoons were inoculated with a commercial recombinant DNA canarypox-vectored CDV vaccine, applying a regimen of two serial doses by SC route with an interval of 25-28 days between doses. The CDV serum virus neutralizing antibody (VNA) baseline titers and the postvaccination titers were measured at fixed time points. Forty percent (8/20) of the wild-caught raccoons had CDV VNA titers of 1:8 or greater upon intake, and all but a single individual were juvenile animals. Approximately one month following the first vaccine dose, 8% (1/12) of raccoons seronegative at baseline had serum CDV VNA titers of 1:24 or greater. Approximately one month following the booster vaccine dose, 67% (8/12) of raccoons seronegative at baseline had serum CDV VNA titers of 1:24 or greater. Among raccoons with CDV VNA titers greater than or equal to 1:8 at baseline, 13% (1/8) demonstrated a fourfold or greater rise in titer one month after the first vaccine dose, whereas 38% (3/8) reached the same threshold one month after the booster dose. The presence of naturally acquired CDV VNA in juvenile raccoons at the time of vaccination may have interfered with the humoral VNA response. A regimen of at least two serially administered SC vaccine doses may be immunogenic for raccoons, but further investigation of alternative routes, regimens, and CDV vaccine products is also warranted for this species.

Mediterranean spotted fever in the Trakya region of Turkey

Mediterranean spotted fever (MSF) is caused by a tick-borne pathogen, Rickettsia conorii subsp. conorii, belonging to the spotted fever group (SFG) rickettsiae. The aim of the present study was to evaluate the cases with confirmed diagnosis of MSF from 2003 to 2009 in the Trakya region of Turkey. Patients with high fever, maculopapular rash (involving the palms or soles) and/or a black inoculation eschar at the site of the tick bite (tache noire) were included in the study. Before doxycycline treatment, skin biopsy specimens, preferably from the eschar or from the maculopapular rash, were obtained for DNA extraction. Immunofluorescence assay (IFA) was performed to detect IgM and IgG antibodies against R. conorii in acute and convalescent sera. Afterwards, a standard PCR reaction using primers suitable for hybridisation within the conserved region of genes coding for outer membrane protein A (ompA) and citrate synthase (gltA) and DNA sequencing were performed. There were 128 patients with confirmed MSF diagnosis. Using IFA, seroconversion or a fourfold or greater rise in titre was observed in 97 (77%) patients, whereas a single high titre was demonstrated in 16 (12.7%) patients. According to PCR analysis, 77 (72.6%) of 106 biopsy samples showed positive results. Of these, 58 (73%) of 79 biopsy specimens were from the eschar and 19 (70%) of 27 specimens were from the maculopapular rash. No significant difference was found between the rate of positive skin biopsies taken from the eschar and the maculopapular rash. DNA sequence analysis was performed to all PCR-positive cases, and R. conorii conorii (type strain: Malish, ATCC VR-613) was detected in each of them. MSF is prevalent, but has been underdiagnosed and underreported so far in Turkey. It is a potentially severe and even fatal disease resembling viral haemorrhagic fevers that has to be included in the differential diagnosis of febrile illness associated with thrombocytopenia, even in the absence of an eschar or a tick bite. While IFA allows for retrospective diagnosis in MSF, advanced molecular techniques provide the rapid detection of rickettsia in all skin samples, including eschar and maculopapular rash.

Phase II meningococcal B vesicle vaccine trial in New Zealand infants

Background:A tailor-made serogroup B outer membrane vesicle vaccine was evaluated in the context of a serogroup B meningococcal epidemic dominated by Neisseria meningitidis strain B:4:P1.7b,4.Objective:To determine the safety, reactogenicity and...

Evaluation of inactivated influenza vaccine in children aged 6–36 months

Approximately 40 children aged 6–36 months were enrolled in a study to evaluate the immunogenicity of the trivalent influenza sub-unit vaccine in the 1999/2000 and 2000/2001 influenza seasons. In 1999/2000, the vaccine dose was 0.1 ml for children aged 6–11 months and 0.2 ml for those aged 12+ months, according to the formulary in Japan. In 2000/2001, the vaccine dose was 0.25 ml, irrespective of age, according to the recommendations of the Advisory Committee on Immunization Practices (ACIP). All children were given two doses approximately 4 weeks apart each year. In 1999/2000, the geometric mean titers and frequency of achieved, protective antibody titers (≧1:40) of children under 12 months of age to those aged 12+ months was 26.3±4.5 vs. 30.9±2.1 ( p=0.582) and 50% vs. 52% ( p=0.0954) for AH1N1 and 42.9±6.4 vs. 192.5±4.3 ( p=0.029) and 60% vs. 87% ( p=0.063) for AH3N2 at 4 weeks after the second vaccinations. In 2000/2001, the geometric mean titers of children under 12 months of age to those aged 12+ months was 17.5±2.9 vs. 126.5±4.2 ( p=0.002) for AH1N1 and 20.1±2.0 vs. 66.7±4.5 ( p=0.039) for AH3N2, respectively, and the frequency of achieved, protective antibody titers was 29% vs. 78% ( p=0.010) and 43% vs. 67% ( p=0.239), respectively. Risk factors including age, vaccine dose (1999/2000 season), vaccination of last year and pre-vaccination titer were assessed by univariate and multivariate analysis to evaluate their associations with the frequency of a four-fold or greater titer rise when comparing HI titers for specimens obtained 4 weeks after the second vaccination and before the first vaccination. In 1999/2000, an independent negative effect was observed for age. In 2000/2001, children under 12 months of age had a lower risk than those over 12+ months for a four-fold or greater titer rise, OR 0.4 (CI 0.05–3.04) for AH1N1 and OR 0.6 (CI 0.11–3.88) for AH3N2. The children under 12 months seemed to exhibit a reduced response to the influenza sub-unit vaccine. The observed values were not statistically significant because our study population was small. These results strongly suggest the necessity for influenza vaccine administration for all household contacts and out-of-home caretakers of children under 12 months old.

Evaluation of clinical usefulness of the microplate agglutination test for serological diagnosis of legionella pneumonia.

Recently, a microplate agglutination test (MPAT) was established for the serological diagnosis of legionella pneumonia. To evaluate its usefulness, this study examined antibody titres in 121 serum samples serially obtained from 40 patients with pneumonia, including 17 cases of confirmed legionella pneumonia. Six of the 17 proven cases became serologically positive within 4 weeks of the onset of pneumonia as assayed by MPAT (cut-off value: four-fold rise to > or = 128 in paired sera or > or = 256 in a single serum specimen), whereas the remaining 11 cases were serologically negative despite serial examination. Four proven cases who were treated with corticosteroids in the acute phase had antibody titres <8 during the first 4 weeks of infection, after which one case showed an elevation in antibody titre for the first time, 13 weeks after the onset of disease. In contrast, all non-proven cases had antibody titres of < or = 64, and only one case developed a four-fold or greater rise in titre. These results indicate that MPAT is a useful method for the laboratory diagnosis of suspected legionella pneumonia, although several false-negative cases were observed. This suggests that the previously established MPAT criteria may require modification, possibly to slightly lower values. These data also indicate that serial examination over the first month of infection may be necessary for serodiagnosis of legionella pneumonia, especially in patients treated with corticosteroids.

Getah virus infection of Indian horses.

An outbreak of disease, characterized by depression, anorexia, fever, limb oedema and lymphocytopenia, occurred on a farm for thoroughbreds in India in 1990. Twenty-six of the 88 horses on the farm were affected, predominantly adults. Signs were present in affected horses for 7-10 days, and the outbreak lasted 21 days. Seven of the 26 affected horses were tested for exposure to Getah virus using paired serum samples, acute and convalescent. Four of the 7 horses seroconverted to Getah virus, and the other three showed a 4-fold or greater rise in titre. The clinical and laboratory findings were similar, but not indentical, to those described in natural and experimental infections in Japanese horses. This is the first description of disease caused by Getah virus infection in horses outside Japan. In addition serum samples from 152 horses from 3 regions of India were evaluated for the presence of antibodies to Getah virus. The seroprevalence was found to be 17%, indicating exposure to the virus elsewhere in Indian horses.

Long-term follow-up study of rubella antibodies in naturally immune and vaccinated young adults

Selective rubella vaccination of 12-year-old schoolgirls was introduced in Sweden in 1973 and at the same time a long-term follow-up cohort study was initiated. In 1982, a two-dose programme with a combined vaccine against measles, mumps and rubella (MMR) was introduced and vaccinations were given at the ages of 18 months and 12 years to both boys and girls. The cohort initially comprised 486 girls. It was followed for between 8 and 16 years. All the girls enrolled were seronegative before vaccination and had seroconverted to a haemagglutination-inhibition (HAI) titre of at least 1:16. On the last test occasion 16 years later, 22% had titre values below 1:16, and 6% lacked detectable antibodies against rubella (<1:8). A fourfold or greater rise in titre was seen in 36% of the girls during the first 8 years of observation, whereas during the following 8 years only 1% showed a significant increase of titre values. The geometric mean titre declined from 1:110 to 1:34 during the first 8 years and further to 1:18 during the following 8 years. From 1982 to 1990, the seroimmunity to rubella of 18-year-old girls and boys was studied yearly. The number studied was 3308 18-year-old schoolgirls and 6347 18-year-old recruits born between 1964 and 1972. The recruits were divided into two groups, 4610 unvaccinated and born in 1964–1969 and 1737 vaccinated and born in 1970–1972. Seropositive recruits in the first group were thus naturally immune only, while the second group had a mixture of natural and vaccine-induced immunity. All the 18-year-old schoolgirls had a mixed type of immunity. The geometric mean of antibody titres against rubella was 1:92 6 years after the vaccination of the schoolgirls. Naturally immune recruits had significantly higher antibody titres (1:160) than the recruits belonging to the vaccinated age group (1:54). However, 23% of the unvaccinated recruits lacked antibodies against rubella.

Waterborne outbreak of Norwalk virus gastroenteritis at a southwest US resort: role of geological formations in contamination of well water

conditions in many parts of the world. In these areas, novel solutions are needed to provide adequate facilities for the treatment of sewage and supply of pure drinking water. From April 17 to May 1, 1989, gastroenteritis developed in about 900 people during a visit to a new resort in Arizona, USA. Of 240 guests surveyed, 110 had a gastrointestinal illness that was significantly associated with the drinking of tap water from the resort's well (relative risk=16·1, 95% confidence interval 14·5 to 17·8) and this risk increased significantly with the number of glasses of water consumed (p <0·005). Three of seven paired sera tested for antibodies to the Norwalk agent had a four-fold or greater rise in titre. Water contaminated with faecal coliforms was traced back to the deep water well, which remained contaminated even after prolonged pumping. Effluent from the resort's sewage treatment facility seeped through fractures in the subsurface rock (with little filtration) directly into the resort's deep well. Although the latest technology was used to design the resort's water and sewage treatment plants, the region's unique geological conditions posed unexpected problems that may trouble developers faced with similar subsurface geological formations and arid climatic conditions in many parts of the world. In these areas, novel solutions are needed to provide adequate facilities for the treatment of sewage and supply of pure drinking water.

Pseudomonas aeruginosa polysaccharide-tetanus toxoid conjugate vaccine: safety and immunogenicity in humans.

A Pseudomonas aeruginosa polysaccharide-tetanus toxoid (Ttxd) conjugate vaccine was produced. Polysaccharide was derived from lipopolysaccharide (LPS) and covalently linked to Ttxd by using carbodiimide with adipic acid dihydrazide as a spacer molecule. The conjugate possessed a relative molecular weight of greater than 350,000 and was nontoxic and nonpyrogenic. The vaccine bound serospecific monoclonal antibodies with an avidity similar to LPS and reacted with murine and human opsonic antibody. The vaccine was immunogenic in rabbits and mice and elicited IgG antibody to both LPS and Ttxd. The vaccine was safe when parenterally administered to humans and evoked only mild, transient reactions. Mean titers of IgG antibody to LPS rose 19-fold after immunization, with 82% of the volunteers responding with a fourfold or greater rise in titer. IgG antibody to LPS evoked after immunization was opsonic and highly effective at preventing fatal experimental burn wound sepsis due to P. aeruginosa.

Streptococcal Pharyngitis

Forty-four children with a clinical diagnosis of streptococcal pharyngitis had throat cultures performed at the initial evaluation and were assigned by randomization to receive either oral penicillin or a placebo for 72 hours. The treating physician, who remained blind to the treatment regimen, recorded the child's temperature and assessed the presence and severity of other signs and symptoms initially and at 24, 48, and 72 hours. The throat culture was positive for group A β-hemolytic streptococci in 26 (59%) of the initial study group, and most of these children developed a fourfold or greater titer rise in antistreptococcal antibodies in their serum, confirming the diagnosis of streptococcal pharyngitis. Statistically significant clinical improvement was observed in the group of 11 children who were later shown to have been taking penicillin compared with the group of 15 who had taken the placebo. Significant differences in the presence and degree of fever and severity of symptoms persisted in the placebo-treated group for 48 hours. We conclude that early penicillin treatment of children with streptococcal pharyngitis significantly alters the acute clinical course of the disease. (<i>JAMA</i>1985;253:1271-1274)

Anomalous antibody responses in viral infection: specific stimulation or polyclonal activation?

Eighteen paired serum samples submitted for serodiagnosis of current infection showed anomalous antibody results by complement fixation test when tested with a battery of agents (viruses, Mycoplasma pneumoniae, and chlamydia) selected for testing on the basis of the symptoms of the patient. Seventeen serum pairs showed a fourfold or greater rise in titer of antibody to two agents in the battery, and one showed only a twofold rise in titer of antibody to the identified causative agent but an eightfold rise in titer of antibody to a heterologous agent. The 18 serum pairs were tested for IgM antibody to the two involved agents to determine whether IgM antibody tests would better distinguish the probable cause of the current infection. The serum pairs were separated into three groups based on their IgM responses. Group I consisted of six serum pairs with IgM antibody to both agents, four pairs of which showed a fourfold or greater rise in titer of IgM antibody to both agents, and two of which showed a rise in titer of IgM antibody to only one of the two agents. Group II consisted of 10 serum pairs with IgM antibody to one of the two agents, 7 pairs of which showed a fourfold or greater rise in titer of IgM antibody to the agent. Group III consisted of two serum pairs with no IgM antibody to either agent. Results show that determination of presence or absence of IgM antibody per se or demonstration of a fourfold or greater rise in specific IgM antibody titer does not always help in distinguishing the causative agent in current infections.

Studies on anti-neuraminidase antibody response in serum after inoculation of influenza hemagglutinin vaccines

This paper reports the serum antibody response to neuraminidase following immunization with various influenza hemagglutinin (HA) vaccines during the years 1978-1981. About 450 volunteers (including adults, high school students, and physically handicapped children) were inoculated with HA vaccines containing type A (H1N1) virus of various CCAeq/ml (A/USSR/92/77, A/Fukushima/103/78, A/Kumamoto/37/79), type A (H3N2) virus (AIYamanashi/2/77, A/Bangkok/1/79) and type B virus (B/Kanagawa/3/76).The results obtained were as follows:HA vaccines used in these studies were less potent in eliciting antibody against neuraminidase than against hemagglutinin. The seroconversion rates (rate of those who showed 3-fold or greater rise in titer) of homologous anti-neuraminidase antibody (ANAb) to vaccinated strains varied from 0 to 40%(10-40% to A/USSR/92/77, 0% to A/Fukushima/103/78, 5% to A/Kumamoto/37/79, 6% to A/Yamanashi/2/77, 12% to A/Bangkok/1/79, 0-38% to B/Kanagawa/3/76). As to A/USSR/92/77 and B/Kanagawa/3/76 strains, the pre-vaccination antibody titers may have affected the seroconversion rates. Good ANAb responses were observed in groups with low titer of pre-vaccination ANAb. Their seroconversion rates were 38-40%. ANAb responses to other strains were low (0-13%). There was no significant rise in ANAb titer to A/Fukushima/103/78, though HI antibody response to the same strain was good (67%).From these results, ANAb responses after immunization of HA vaccine were not satisfactory, and future studies for potent vaccine are required.

Antibodies to Chlamydia trachomatis, Mycoplasma hominis, and Neisseria gonorrhoeae in sera from patients with acute salpingitis.

Paired sera from 60 consecutive patients with acute salpingitis, confirmed by laparoscopy, were examined for serum antibodies to Chlamydia trachomatis, Mycoplasma hominis, and Neisseria gonorrhoeae. By a microimmunofluorescence (MIF) test IgM or IgG antibodies to C trachomatis or both were present in sera from 80% of the patients' by indirect haemagglutination (IHA) tests antibodies to M hominis and N gonorrhoeae pilar antigens were present in 40% and 18% respectively. In a control group of 50 pregnant women antibodies to the same three organisms occurred in 8%, 8%, and 6%. Evidence of current chlamydial infection was found in 35 (58%) and of current gonococcal infection in five (8%) of the 60 patients by culture or serological tests or both. The results of chlamydial antibody tests correlated with the severity of the tubal inflammation (as shown by laparoscopy) and the duration of the lower abdominal pain before attendance. The predictive values of a positive and a negative MIF test result were 44% and 83% respectively and of the IHA gonococcal antibody test 36% and 100% respectively. Significant rises in titre of antibodies to M hominis were found in 12% of patients. A four-fold or greater rise in titre indicated probable double infections with chlamydia and mycoplasmas in 7% of patients. Thus, at present gonococcal salpingitis appears to form only a small proportion of all cases of salpingitis in southern Sweden, and in patients with nongonococcal salpingitis infections with C trachomatis and M hominis commonly occur.

Secretory immunological response in infants and children to parainfluenza virus types 1 and 2.

The secretory immunological responses to natural infection with parainfluenza viruses ae not well defined. Nasopharyngeal secretion specimens from 20 infants and children naturally infected with parainfluenza virus type 1 or type 2 were examined for class-specific antibody and virus-neutralizing activity. There was a marked discordance in individual secretions between immunoglobulin A (IgA) antibody (as measured by indirect immunofluorescence) and neutralizing activity (as determined by either hemadsorption plaque or 50% tissue culture infective dose reduction) to the infecting parainfluenza virus type. Many secretions contained neutralizing activity in the absence of detectable IgA antibody; conversely, secretions with measureable IgA antibody frequently lacked neutralizing activity. Moreover, there was no relationship between neutralizing activity and the course of illness. All 11 patients with serial secretion specimens showed a fourfold or greater titer rise in IgA antibody to the homologous parainfluenza virus type. Antibody usually appeared 7 to 10 days after the onset of symptoms and peaked at about 2 weeks. This response did not appear to be related to age or to severity of illness. in general, the secretory responses resembled those seen in infants infected with respiratory syncytial virus.

SEROLOGICAL RESPONSE OF PATIENTS WITH NON-GONOCOCCAL URETHRITIS TO CAUSATIVE ORGANISM OF CONTAGIOUS EQUINE METRITIS 1977

The presence of agglutinins to the causative organism of contagious equine metritis (C.E.M.) in human serum has been confirmed. Agglutinins were found in the serum of 84 (37·6%) of 223 patients with non-gonococcal urethritis (N.G.U.), and in 12·5% of these patients there was a four-fold or greater rise in titre during the course of their illness. There was no evidence that these agglutinins were the result of infection by chlamydiæ or ureaplasmas. Certain patients with these agglutinins seemed to respond better to therapy with antibiotics to which the C.E.M. bacterium is susceptible in vitro than did patients in whom these agglutinins were not found. The findings suggest that the C.E.M. bacterium or a microorganism related to it may be ætiologically involved in a proportion of patients with N.G.U. A search for such an organism in these patients is in progress.

The Natural History of Recurrent Facial-Oral Infection with Herpes Simplex Virus

Fifty-seven episodes of facial-oral infections with herpes simplex virus (HSV) (cold sores) were studied in 41 ambulatory patients. Patients were examined within 24 hr of the onset of symptoms and for five consecutive days. Clinical parameters were assessed, lesion size was measured, and daily cultures for virus were performed. HSV was isolated in 61% of the episodes and was HSV type 1 in all cases. Serum neutralizing antibody to HSV was measured initially and 21 days after the onset of symptoms. All patients had antibody initially, but a fourfold or greater rise in titer was seen in only four patients. Lesion size and stage of healing were compared in patients with virus-positive episodes and those with virus-negative episodes. These two groups were found to be clinically distinct. Virus-positive lesions were larger, and the rate of healing was slower. This finding provides the first clinical correlation associated with the presence of HSV in cold sores.

Relative Importance of Viruses and Bacteria in the Etiology of Pediatric Diarrhea in Taiwan

Of 80 children with acute gastroenteritis in Taiwan, 75 were tested for evidence of infection with a reovirus-like agent (RVLA) by electron microscopic examination of stools and/or by assays of complement-fixing and immunofluorescent antibody responses to the serologically related Nebraska calf diarrhea virus; 42 (56%) were positive. Of children whose stools contained the agent, 90% showed a fourfold or greater rise in titer of immunofluorescent antibodies, and 85% developed a fourfold or greater rise in titer of complement-fixing antibodies to the agent. Strains of Escherichia coli producing only heat-labile toxin (LT) were isolated from 7% of 57 ill children who had not received previous antibiotics and from 4% of 131 healthy control children (P = 0.49). Strains of E. coli producing only heat-stable toxin (ST) were isolated from five (9%) of 57 age-matched children in the group of 131 healthy controls tested. Invasive E. coli were not found. In addition, three of six children with bacterial and! or serological evidence of an infection with LT-producing E. coli and four of five children infected with ST-producing E. coli had infections with RVLA. RVLA appeared to be the major cause of diarrheal illness in Taiwan during the summer of 1975, whereas toxigenic E. coli appeared to be responsible for a smaller proportion of pediatric enteritis.

Leptospirosis—Induced abortion

History and Clinical Signs : Icterus, anemia and fever may accompany or precede the abortion. Most frequently there are no easily detected clinical signs of infection of the dam preceding abortion. Gross Lesions : No gross lesions occur consistently in fetuses aborted due to leptospirosis. The fetus may be expelled soon after its death or 24 to 48 hours after death. Occasionally calves from infected dams may be born alive, but weak and often die within hours. Microscopic Lesions : No microscopic lesions occur consistently in the fetal tissue. Cultural Procedures : Isolation of leptospires from the tissues of the aborted bovine fetus is rarely possible. Isolation of leptospires from the urine of the cow within a week to 10 days after abortion is frequently possible. This provides absolute evidence of infection and presumptive evidence of the cause of the abortion. Serologic Procedures : A single positive microscopic agglutination test (MA) with a titer 1:100 or greater does not distinguish between infected and recovered animals. A four (4) fold or greater rise in titer in paired serum samples, one taken soon after abortion and the other 7 to 10 days later, is reasonable evidence of an active infection and presumptive evidence of the cause of the abortion. The lack of a titer rise in paired serum samples does not rule out leptospirosis as the cause of the abortion. Special Procedures : Demonstration of leptospires in fetal tissue or placenta by Levaditi's Warthin Starry stain, or fluorescent antibody (FA) technique is desirable, but seldom successful. Preferred Diagnostic Methods : 1. 1. Isolation of leptospires from, or demonstration of them in, the tissues of the aborted fetus or its placenta. 2. 2. Isolation of leptospires from, or demonstration of them in, the urine of the aborting dam within about 2 weeks after abortion. 3. 3. Demonstration of 4 fold or greater increase in MA antibody titer to a leptospiral serotype in the second of 2 blood samples from the aborting dam, one sample taken near the time of abortion and the other 7–10 days later. Failure to demonstrate a rising titer does not rule out leptospirosis as the cause of the abortion. Occasionally an infected animal will not develop a demonstrable titer.

Epidemiologic survey of rubella in a military recruit population.

A seroepidemiologic surveillance of rubella infections in arriving male and female Navy recruits indicated that from 82-90% of young adults have hemagglutination (HA) titers of 1:10 or greater. Subsequent to the establishment of a new male recruit camp, there was a 10- to 11-month hiatus of low level rubella infection in the population. Once endemic rubella was established, more than 73.3 per cent of those with no detectable initial titer seroconverted. There was no reported rubella infection at an isolated female recruit camp of about 500 women even though the proportion of susceptibles was similar. However, once the female recruit camp was relocated within the male camp, their experience with rubella became comparable. A small (6.8% men, 5.6% women) number of recruits with pre-existing HA antibody titers had a four-fold or greater rise in titer during training. The great transmissibility of rubella virus in a closed population was illustrated and the ineffectiveness of herd immunity in this setting was evident.

DIAGNOSIS OF RECENT HERPES SIMPLEX INFECTIONS.

A modified, indirect immunofluorescent technique for the detection of specific serum Herpes simplex virus IgM antibodies is described. The previously necessary long incubation period with the serum for the determination of the IgM fluorescent antibody titre, is reduced from 3 to 1 hour after staphylococcal adsorption of IgG. This IgM test will also, in contrast to the previous procedure with untreated sera, give a more reliable and easy determination of the IgM titres, because the IgM fluorescence is more intense. Paired sera from 34 patients, taken approximately 6 and 15 days after the onset of symptoms, were examined. Sera from 11 patients showed a fourfold or greater rise in titre in the CFT and the IgG fluorescent antibody test, and 7 of these showed also a fourfold or greater rise in the IgM fluorescent antibody titre. The sera from the other patients, however, showed a constant titre in the CFT and the IgG fluorescent antibody test and were negative in the IgM test. The results show that in many cases a current Herpes simplex infection rapidly can be identified by this immunofluorescent technique.