Long-term findings in patients with facial palsy and antibodies against Borrelia burgdorferi

Little is known about the long-term effects of Borrelia burgdorferi (Bb) infection in untreated patients with peripheral facial palsy. We investigated 12 patients with elevated serum Bb antibody levels, with a median follow-up time of 11 years, during which 3 of the 12 still exhibited intrathecal antibody production of antibodies against Bb flagellar antigen, and 2 of the 3 had normal serum Bb antibodies. Four of the 12 had elevated serum antibody titres at the late follow-up examination. Arthralgia, reported by 7 patients, was the single most common complaint. Four patients showed extensive oculomotor disturbances, which were not correlated to antibody titres or intrathecal antibody synthesis. In 1 of the patients with intrathecal Bb antibody production, most symptoms were eradicated by antibiotic treatment 6 years after the initial infection. We conclude that even several years after a Bb infection, intrathecal Bb antibody production can still occur in serum Bb IgG antibody negative patients with a history of facial palsy.     

Neuroborreliosis

Neuroborreliosis, a manifestation of infection with the spirochete Borellia burgdorferi, has become the most frequently recognised arthropod-borne infection of the nervous system in Europe and the USA. The best criterion of an early infection with B. burgdorferi is erythema migrans (EM), but this is present in only about 40-60% of patients with validated borreliosis. Therefore use of the duration of the disease as a classification criterion for neuroborreliosis is increasing, the chronic form being distinguished from the acute when symptoms persist for more than 6 months. The diverse manifestations of neuroborreliosis require that it be included in the differential diagnosis of many neurological disorders. In Europe, meningopolyradiculoneuritis (Bannwarth's syndrome) represents the most common manifestation of acute neuroborreliosis, with the facial nerve being affected much more frequently than the other cranial nerves. Clinical symptoms affecting the central nervous system are rarely observed and then mostly in chronic courses. By far the most common manifestation of chronic neuroborreliosis is encephalomyelitis with spastic-ataxic disturbances and a disturbance of micturition. The current diagnosis of neuroborreliosis is a clinical one, which has to be confirmed by laboratory testing. In most patients, examination of the cerebrospinal fluid (CSF) reveals lymphocytic pleocytosis, damage to the blood-CSF-barrier and an intrathecal synthesis immunoglobulin (Ig) M, IgG, and sometimes IgA. Confirmation of a borrelial infection of the nervous system requires demonstration of an intrathecal synthesis of borrelial-specific antibodies in the CSF or detection of borrelial DNA in the CSF by polymerase chain reaction (PCR). There is no generally accepted therapeutic regime for the treatment of neuroborreliosis, but recent studies have shown ceftriaxone 2 g/day and cefotaxime 6 g/day to be effective in acute and chronic courses. Penicillin G 20 mega units/day and doxycycline 200 mg/day may be suitable for uncomplicated meningopolyneuritis, without involvement of the central nervous system. The durationof treatment--at least 2 weeks in the acute forms and 3 weeks in the chronic forms of neuroborreliosis--is very important for successful treatment. Corticosteroids are recommended only for patients with severe pain that does not respond to antibiotics an analgesics.     

Reversal of Borrelia burgdorferi associated dilated cardiomyopathy by antibiotic treatment?

It is suggested that Borrelia burgdorferi infection could be associated with dilated cardiomyopathy (IDC). Stanek et al. were able to cultivate Borrelia burgdorferi from myocardial biopsy tissue of a patient with longstanding dilated cardiomyopathy. Here we present a study in which we examined the effect of standard antibiotic treatment on the left ventricular ejection fraction (LVEF) in patients with dilated cardiomyopathy associated with Borrelia burgdorferi infection. In this study we assessed the serum (IgG, IgM Elisa) and history of 46 IDC patients with specific regard to Borrelia burgdorferi infection (mean LVEF 30.4 +/- 1.3%, measured by cardiac catheterization and echocardiography with the length-area-volume method). All 46 patients received standard treatment for dilated cardiomyopathy: ACE inhibitors, digitalis, and diuretics. Eleven (24%) patients showed positive serology and a history of Borrelia burgdorferi infection; nine of these also had a typical history of tick bite and erythema chronicum migrans (ECM) and/or other organ involvement, and two had no recollection of tick bite or ECM but showed other Borrelia burgdorferi-associated disorders (neuropathy, oligoarthritis). These 11 patients with Borrelia burgdorferi infection received standard antibiotic treatment with intravenous ceftriaxone 2 g bid for 14 days. Six (55%) recovered completely and showed a normal LVEF after 6 months, three (27%) improved their LVEF, and two (18%) did not improve at all. This amounts to nine (82%) patients with recovery/improvement in the Borrelia burgdorferi group. The 35 patients who did not show positive serology or a history of Borrelia burgdorferi infection did not receive antibiotic treatment. In this group without Borrelia burgdorferi infection 12 (26%), showed recovery/improvement following the standard treatment of dilated cardiomyopathy (see earlier). Our results indicate that Borrelia burgdorferi infection could play a decisive role in the development of dilated cardiomyopathy, especially in a geographical region such as Graz, where Borrelia burgdorferi is endemic. While we are aware of the small number of Borrelia burgdorferi patients in this study, we nevertheless conclude that in a remarkable number of patients with signs of Borrelia burgdorferi infection, dilated cardiomyopathy could be reversed and LVEF improved.     

Mutagenicity and amount of chloroform after chlorination of bank filtered lake water

A one-step immunoassay for simultaneous detection of serum IgG and IgM antibodies to Borrelia burgdorferi has been developed. The assay is based on C1q, which binds to immune complexes containing IgG and/or IgM antibodies. Micro-beads pre-coated with antibodies to human C1q are mixed with human serum samples and fluorochrome-labelled B. burgdorferi flagellum antigen. In the presence of serum IgG and/or IgM antibodies to B. burgdorferi, fluorochrome-labelled antigen/antibody complexes are formed. These are then bound by serum C1q and are subsequently captured on the anti-C1q-coated beads. The sample is analysed on a flow cytometer and the presence of fluorescent beads is, thus, indicative of a positive test result. In the present study the sensitivity and specificity of the assay are compared to those of the indirect IDEIA B. burgdorferi IgG and the mu-chain capture IDEIA B. burgdorferi IgM ELISAs for separate determination of IgG and IgM. Detection using a flow cytometer can be performed without separation of the beads from the reaction mixture, which means that in practice, the method is carried out as a one-step assay and it is, thus, very suitable for automation. Other advantages of this kind of assay includes an antibody/antigen reaction which occurs in solution and the potential of using the method for the detection of antibodies against several antigens from the same or different infectious agents (multi-parameter screening).     

Diagnostic tools in Lyme borreliosis: clinical history compared with serology

The occurrence of a history of clinical Lyme borreliosis and the prevalence of positive antibodies to Borrelia burgdorferi were studied in 431 Dutch hunters. The majority of the hunters (336 or 78%) did not report any complaints and had no positive IgG antibodies to B. burgdorferi. Sixty-five hunters (15.1%) had no clinical manifestations but did not have positive antibodies to B. burgdorferi. Only 1.9% of the population studied had had past symptoms of definite or probable Lyme borreliosis. Likelihood ratios were high (21.3) for the recognition of erythema migrans, but much lower for tick bites (3.6) or positive IgG Lyme serology (3.5). Clinical history turned out to be a more powerful diagnostic tool than Lyme serology.     

Structural characterization of recombinant human erythropoietins by fluorophore-assisted carbohydrate electrophoresis

Two enzyme immunoassay (EIA) systems were compared for their ability to detect Borrelia burgdorferi sensu lato specific IgG and IgM antibodies and to differentiate between symptomatic (83 patients with neuroborreliosis) and asymptomatic seropositive subjects (80 healthy controls). Antibody concentrations were determined by EIA; the antigens used were either a sonicate of B. burgdorferi or three recombinant borrelial proteins: the 14-kDa flagellin fragment, the outer surface protein C (22 kDa) and the high molecular mass protein p83 (83 kDa). In the sonicate, EIA, IgG or IgM antibodies to B. burgdorferi, or both, were detected in all patients with neuroborreliosis and in all controls. Pre-absorption of sera with Treponema phagedenis sonicate diminished the sensitivity of detection of borrelial specific IgG (IgG or IgM or both) antibodies in patients with neuroborreliosis from 80 to 57% (100 to 82%) and in the controls from 100 to 32% (100 to 37%). While being specific for B. burgdorferi, the recombinant EIAs proved to be significantly more sensitive than the sonicate EIA: IgG or IgM, or both antibodies against any of the recombinant antigens were detected in 92% of patients with neuroborreliosis and in 24% of controls. The increase in sensitivity in patients with neuroborreliosis was mostly due to the higher detection rate of IgM antibodies in the recombinant EIA (77% versus 48% in the sonicate EIA), while IgG antibodies were demonstrated with similar frequencies in both EIA systems (57% versus 60%). It was concluded that the recombinant EIAs are superior to the sonicate EIA with pre-absorption of cross-reactive antibodies in the confirmation of an acute borrelial infection and in the differentiation between symptomatic and asymptomatic infections.     

Rheumatic manifestations in Lyme borreliosis: personal experience in patients with oligoarthritis of "unknown" origin

Lyme borreliosis is an infectious illness caused by the spirochete Borrelia burgdorferi and is transmitted by tick vectors. A prospective study was performed from January 1990, to investigate whether Lyme arthritis might have been undetected among patients with (unclassified arthritis) oligoarthritis of "unknown" aetiology. 210 patients were tested for antibodies to Borrelia burgdorferi: 82 patients with oligoarthritis of "unknown" aetiology; 52 patients with Reiter's syndrome; 20 patients with seronegative, B-27 positive oligoarthritis and 56 controls. Serological testing for Borrelia burgdorferi was performed by indirect immunofluorescence assay. The occurrence of positive antibodies (1:80) in 11 (13.4%) patients with arthritis of "unknown" aetiology was significantly different from the combined control group (1.6%) (p < 0.05). Four out of 11 patients remembered a tick bite, two out of 11 patients developed erythema migrans after 3 to 10 days. Six weeks later 2 patients developed oligoarthritis and one patient after a month. In the remaining 8 patients arthritis was the first sign of the disease. Knees were most commonly affected (90%). Radiographic abnormalities (osteoporosis, soft tissue swelling) were noted in 3 patients. The synovial fluid findings were typical for inflammatory arthritides in 6 patients. The diagnosis of Lyme borreliosis was made according to following data: origin from an area endemic for Lyme borreliosis, tick bite, erythema migrans, significant levels of the antibodies to the Borrelia burgdorferi and oligoarthritis. It can be concluded that arthritis may be the main manifestation of Borrelia burgdorferi infection.     

Quantitation of intrathecal measles virus IgG antibody synthesis rate: subacute sclerosing panencephalitis and multiple sclerosis

A method for quantitating specific anti-viral antibodies in serum and cerebrospinal fluid (CSF) is established using enzyme-linked immunosorbent assay (ELISA). Quantitated antibody levels are used to determine intrathecal specific IgG synthesis rate for the particular antibody. Measles virus was used as a model for validating this quantitative technique: a mutated form of measles virus is a cause of subacute sclerosing panencephalitis (SSPE) and there is a possibility that measles virus is related to the cause of multiple sclerosis (MS). Matched serum and CSF samples were assayed. Concentration of anti-measles IgG was determined and intrathecal measles-specific IgG synthesis rate was calculated. For the SSPE samples, measles-specific IgG synthesis rate was elevated and comprised > 20% of the total intrathecal IgG synthesis rate; these results are consistent with the literature. The ELISA method can be performed routinely, providing a quick, simple, reproducible means of quantitating specific antibody concentrations, with sensitivity greater than 1 nanogram per milliliter. With this method, quantitation of IgG antibodies to any other viral antigen can be reliably and precisely determined.     

Mononeuropathy multiplex in rhesus monkeys with chronic Lyme disease

Peripheral neuropathy is a recognized but poorly understood manifestation of Lyme disease. We performed serial electrophysiological studies on 8 rhesus monkeys chronically infected with the JD1 strain of Borrelia burgdorferi and compared the results with those of similar studies on 10 uninfected control monkeys. Four infected and 2 uninfected animals underwent sural nerve biopsy. Five of the infected and 1 of the uninfected animals also had postmortem neuropathological examinations. Altogether, 5 of the infected monkeys demonstrated primarily axonal-loss-variety multifocal neuropathies. Only one nerve lesion exhibited findings compatible with demyelination. Pathologically, peripheral nerve specimens showed multifocal axonal degeneration and regeneration and occasional perivascular inflammatory cellular infiltrates without vessel wall necrosis. Free spirochetal structures were not seen, but several macrophages exhibited positive immunostaining with a highly specific anti-B. burgdorferi, 7.5-kd lipoprotein monoclonal antibody. In the infected animals, serial analysis of serum antibodies to B. burgdorferi showed increasing numbers of IgG specificities and new IgM specificities, suggesting persistent infection. Thus, peripheral neuropathy in the form of a mononeuropathy multiplex develops frequently in rhesus monkeys chronically infected with B. burgdorferi. The pathogenesis of these nerve lesions is not yet known, but our studies suggest an immune-mediated process perhaps driven by persistent infection with B. burgdorferi.     

Heterogeneity of BmpA (P39) among European isolates of Borrelia burgdorferi sensu lato and influence of interspecies variability on serodiagnosis

The molecular and antigenic variabilities of BmpA (P39) among European isolates of Borrelia burgdorferi were analyzed. The bmpA sequences of 12 isolates representing all three species of B. burgdorferi sensu lato pathogenic for humans were amplified by PCR, cloned, and sequenced. The BmpA protein of Borrelia garinii is heterogeneous, with an amino acid sequence identity ranging from 91 to 97%, whereas the BmpA proteins of Borrelia afzelii and B. burgdorferi sensu stricto strains appear to be highly conserved (>98.5% intraspecies identity). The interspecies identities ranged from 86 to 92%. Cluster analysis of BmpA reflected the subdivision of B. burgdorferi sensu lato isolates into the three species as well as a considerable heterogeneity among B. garinii strains. The BmpA protein of each species of B. burgdorferi sensu lato was recombinantly expressed in Escherichia coli, purified, and used to generate monoclonal antibodies. Seven BmpA-specific antibodies were identified; six of them recognized conserved epitopes of all three species, whereas one was specific for BmpA of B. afzelii and B. garinii. A monoclonal antibody (H1141) recommended by the Centers for Disease Control and Prevention for use in the standardization of immunoblots showed strong reactivity with BmpA of B. burgdorferi sensu stricto but no or only weak reactivity with BmpA of B. garinii and B. afzelii, respectively. Sera from 86 European patients with Lyme borreliosis in different stages and 73 controls were tested in immunoglobulin G (IgG) and IgM immunoblots with the recombinant BmpA proteins of the three species, revealing specificities of 98.6 to 100%. IgM antibodies against recombinant BmpA were only rarely detected (1.1 to 8.1%). With the BmpA proteins of B. afzelii and B. garinii, sensitivities for the IgG test (sera from stages I to III) were 36.0 and 34.9%, respectively, in contrast to 13.9% with BmpA of B. burgdorferi sensu stricto. Therefore, we recommend that recombinant BmpA of B. afzelii or B. garinii should be used solely, or in addition to B. burgdorferi sensu stricto BmpA, in serodiagnostic tests for Lyme borreliosis in Europe.     

Prevalence of Borrelia burgdorferi serum antibodies in 651 patients with predominantly neurologic diseases

An analysis was undertaken to the records of 651 patients (median age 51 years, range 1-91; 334 male and 317 female patients), who were admitted for various reasons to the department of neurology and psychosomatics of the county hospital in Villach (K?rnten, Austria), over the period of one year. The clinical diagnoses were mostly neurological and psychiatric (n = 599), involving 25 different conditions. Other diagnoses (n = 52) comprised a group of 13 various conditions. Sera of all these patients were tested for antibodies to Borrelia burgdorferi. Overall seropositivity was 37.8%. Seropositivity increased significantly with age (p < 0.01). Seroprevalence exceeded 40% in patients with meningitis, paresis of the cranial nerves, cervical syndrome, pareses and sponylitis. The erythrocyte sedimentation rate (ESR) was raised in 37.9% of cases which was not related to seropositivity. ESR was significantly increased in patients with lumbago (p < 0.01) and with arthritis (p < 0.05). Antibiotics and dosages used were recorded in 164 cases. All these cases improved after therapy. Of 81 patients with a history of tick bite, 43 (53%) were seropositive. This is a significantly higher incidence than that of patients without tick bites (p < 0.01). The retrospective evaluation of patients' records showed that anamnestic and clinical findings alone do not suffice to establish the specific diagnosis of Lyme borreliosis and, hence, do not provide the indication of appropriate therapy. Furthermore, the mere demonstration of serum antibodies to Borrelia burgdorferi does not give information on the current state of infection. In case of a suspected Borrelia burgdorferi infection confirmatory tests are needed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fatal encephalitis caused by concomitant infection with tick-borne encephalitis virus and Borrelia burgdorferi

We describe a 38-year-old farmer from the southwestern archipelago of Finland where both tick-borne encephalitis (TBE) virus and Borrelia burgdorferi are endemic. He presented with fever and headache, developed severe meningoencephalitis in 3 days, and, after 1 month, died without regaining consciousness. High titers of IgG and IgM antibodies to TBE virus were present in both serum and CSF. Serology for Borrelia was negative. Autopsy revealed necrotizing encephalitis and myelitis with involvement of the dorsal root ganglion. With use of polymerase chain reaction tests, segments of two separate genes of B. burgdorferi were amplified from the patient's CSF. This case demonstrates that the possibility of dual infection should be considered for patients residing in geographic areas where Ixodes ticks may carry both the TBE virus and B. burgdorferi. We believe that the most severe damage in this case was caused by TBE virus rather than by B. burgdorferi. Nevertheless, the coinfection might have contributed to the fatal outcome that has not been previously observed in Finnish patients with TBE.     

A population-based seroepidemiologic study of human granulocytic ehrlichiosis and Lyme borreliosis on the west coast of Sweden

Ehrlichioses are emerging infections in the United States. Human granulocytic ehrlichiosis (HGE) and Lyme borreliosis (LB) are acquired after Ixodes ricinus-complex tick bites. An ongoing seroepidemiologic study of the 185 of the 356 permanent residents of the Koster Islands in Sweden was expanded to include ehrlichioses. Ehrlichial antibodies were measured by IFA using Ehrlichia equi and Ehrlichia chaffeensis. Borrelia burgdorferi IgG ELISA-seropositive subjects were confirmed by Western blot. E. equi and E. chaffeensis antibodies (titer > or = 80) were found in 21 (11.4%) and 2 (1.1%) of 185 samples, respectively. Antibodies to B. burgdorferi were found in 25 (13.5%) of 185. Six persons were seropositive for both HGE and LB. Among data from questionnaires, clinical symptoms, antibiotic treatments, or tick bites were not more frequent in E. equi- or B. burgdorferi-seropositive than -seronegative persons. The seroprevalence of HGE was similar to that of Lyme borreliosis. Prospective studies of European HGE are needed.     

The Norwegian Polio Study 1994: a nation-wide survey of problems in long-standing poliomyelitis

BACKGROUND: Sarcoidosis is a multisystemic granulomatous disease of unknown etiology, while Lyme borreliosis is a multisystemic disorder caused by Borrelia burgdorferi. The purpose of this study is to evaluate the relationship between sarcoidosis and Lyme borreliosis in a region of Japan where Lyme borreliosis is endemic. METHODS: We determined the seroprevalence of anti-Borrelia burgdorferi antibodies as well as antibodies three Japanese Borrelia strains by enzyme-linked immunosorbent assay and dotblot assay using purified Borrelia-specific proteins in 46 patients with confirmed sarcoidosis and 150 controls (50 disease controls and 100 healthy controls) in Hokkaido, the affected region. RESULTS: Fifteen patients with sarcoidosis (32.6%) tested positive for Borrelia spirochete in both assays, compared with two disease controls (4.0%) and two healthy controls (2.0%). The seroprevalence of anti-Borrelia antibodies in patients with sarcoidosis was much higher in the affected region than in the region in our previous study were Lyme borreliosis is non-endemic. CONCLUSION: In a region where Lyme borreliosis is endemic, Borrelia infection may be partially associated with sarcoidosis.     

The clinical instrumental characteristics of the locomotor involvement in patients who have had Lyme disease

Locomotor system has been studied in 24 patients with a history of Lyme's disease. All of them had arthralgia, 11 had relapsing arthritis, chronic arthritis occurred in 6 examinees. Arthritis presented as recurrent asymmetric mono-oligoarthritis affecting primarily joints of the lower limbs. Periarticular disorders were detected in 12 patients. Serologically, 18 of 24 patients had elevated titers of antibodies to Borrelia burgdorferi in indirect immunofluorescence test. Scintigraphy revealed polyarticular lesions in many cases, ultrasound investigation of the joints confirmed inflammatory nature of the pathological changes. It is inferred that combined methods of examination in diagnosis of Lyme's arthritis (titers to antibodies to Borrelia burgdorferi, ultrasound investigations, scintigraphy of the joints) provide most complete information.     

Lyme disease in Chile. Prevalence study in selected groups

BACKGROUND: The prevalence of Lyme disease in Chile is unknown. AIM: To study the existence and epidemiology of Lyme disease in Chile. PATIENTS AND METHODS: One hundred eighteen patients with signs or symptoms suggestive of Lyme disease were studied. Antibodies against Borrelia burgdorferi were measured using ELISA and indirect immunofluorescence screening tests. Positive cases were confirmed with ELISA using a purified antigen and Western Blot analysis. Human biological samples and ticks were cultured in BSK-H medium. RESULTS: Five patients, three with dermatological manifestations and two with facial palsy and other neurological symptoms, had antibodies against Borrelia, measured by ELISA and indirect immunofluorescence. However the presence of IgM antibodies by ELISA using purified antigen, was confirmed in only one case. All sera and cerebrospinal fluids were negative on Western Blot Analysis. No plasma, skin, CSF or thick culture yielded Borrelia CONCLUSIONS: We could not confirm the existence of Lyme disease in Chile. Positive screening with negative confirmatory test suggests false positive non-specific reactivity or that local Borrelia are antigenically different compared to North American strains.     

Ankle arthrodesis with cross screw fixation. Good results in 36/40 cases followed 3-7 years

From May 1991 to May 1994, Lyme borreliosis was studied prospectively in 301 residents living on Asp?, a highly endemic area for the disease. The study included annual questionnaires and blood samples for serology. Immunoglobulin G (IgG) antibodies to Borrelia burgdorferi sensu lato were detected by enzyme-linked immunosorbent assay in 63/301 (21%) of the residents at the start of the study. Seropositivity rates increased with time, and 3 years later 101/301 (34%) were positive. A total of 34 individuals developed physician-verified manifestations of Lyme borreliosis during the study period. Nine individuals developed an erythema migrans, despite a previously treated Lyme borreliosis or pre-existing high levels of IgG antibodies to B. burgdorferi s.l.     

Cardiac transplantation

The authors performed a clinical and serologic follow-up study after 4.2 +/- 1.2 years in 44 patients with clinical signs of neuroborreliosis and specific intrathecal antibody production. All patients had been treated with ceftriaxone 2 g/day for 10 days. Although neurologic deficits decreased significantly, more than half the patients had unspecific complaints resembling a chronic fatigue syndrome and showed persisting positive immunoglobulin M serum titers for Borrelia in the Western blot analysis.     

FlaA, a putative flagellar outer sheath protein, is not an immunodominant antigen associated with Lyme disease

FlaA was recently found to be associated with flagellar filaments of Borrelia burgdorferi. We tested whether antibodies to this protein are a good indicator of infection, as antibodies to FlaA proteins in other spirochetal infections show an increase in titer. Although overproduction of intact FlaA was highly toxic to Escherichia coli, truncated proteins which lacked the N-terminal signal sequence could be successfully overexpressed. Immunoblotting with sera from mammalian hosts infected with B. burgdorferi indicated that FlaA is not an immunodominant antigen in Lyme disease. However, sera from two patients reacted with both recombinant and native FlaA protein, suggesting that B. burgdorferi FlaA was antigenic and expressed in vivo.     

Follow-up in 103 patients with catecholamine-secreting tumours

BACKGROUND: It is necessary to have an easy and quickly test to distinguish "false positive" rubella IgM results and residual antibodies from the antibodies produced in the primary infection, in pregnant women. The avidity of IgG antibodies test seems to differentiate between primary rubella infection and past infections, reinfections or postvaccination, showing its utility in the diagnosis of primary infection in other infectious diseases. METHOD: For 30 months, 178 sera from 157 patients with clinical and/or epidemiological rubella suspicion or with a positive rubella IgM result as result of an accidental serological finding, were remitted to our laboratory for a serological follow up. We distinguished 3 patient groups: outbreak group, 112; pregnant women, 36, and newborn 11. Rubella IgM antibodies by indirect EIA previous the rheumatoid factor absorption; IgG antibodies of low avidity by indirect EIA previous treatment of serum with 6 M urea, were detected in the sera. It considered a positive result, a rubella avidity index (AI) < 50%. RESULTS: In the epidemic outbreak group, 90.2% of the patients were not vaccinated. 80% of cases occurred in young men between 14 an 20 years old. From 109 patients (97.3%) with rubella IgG antibodies, 92 (84.4%) showed AI-IgG lower than 50%. In this group, the mean rate of AI-IgG rubella was 29.0%. In the pregnant women group, except for two of them, rubella IgM antibodies were an accidental finding in a serological pregnancy screening. Thirty patients (83.8%) showed AI-IgG rubella > 50%. The two pregnant women who had evidence of clinical and epidemiological rubella showed AI-IgG rubella of 37.4% and 20.9%. Another four pregnant women showed AI-IgG rubella close to cut-off (44.7-49.0%). The mean AI-IgG rubella in this group was 71.8%. The mean AI-IgG Rubella between the epidemic outbreak group and the pregnant women group, 29.0 and 71.8% respectively, was statistical significance (p < 0.001). CONCLUSIONS: The avidity IgG test is simple and quickly, and it allow to exclude most of positive results because of residual IgM antibodies and false reactive.