Measles virus-specific immunoglobulin G isotype immune response in early and late infections.

A total of 154 human serum samples (32 acute-phase and 22 convalescent-phase serum samples obtained within a week and between days 8 and 26 after the onset of rash, respectively, and 100 samples drawn from healthy immune adults) were processed by an immunofluorescence assay for the detection of immunoglobulin M (IgM), total immunoglobulin G (IgG), IgG1, IgG2, IgG3, and IgG4 measles virus-specific antibodies. In the acute phase, IgG1 was seen first, followed by IgG2, IgG3, and IgG4 responses, the mean seropositivity of which gradually increased during convalescence, reaching 100% (standard deviation [SD], 84 to 100%), 57% (SD, 34 to 80%), 86% (SD, 66 to 100%), and 86% (SD, 66 to 100%), respectively. IgG2 rose and fell in connection with IgG3 subclass antibodies, showing a rate of detection of IgG2 and/or IgG3 subclass antibodies of 95.5% (range, 100 to 86.5%) in the convalescent phase of infection. The mean percentage of measles IgG2 and IgG3 seropositivity dropped significantly during the memory phase, to 2% (range, 2 to 6%) and 3% (range, 3 to 7%), respectively (P < 0.05); meanwhile IgG1 and IgG4 subclass responses remained relatively unmodified in samples obtained years after infection (mean 100% [SD, 96 to 100%] and 86% [SD, 79 to 93%], respectively). Results obtained defined two highly different immune isotypic response patterns. One pattern is restrictive to IgG2 and/or IgG3 in the convalescent phase and is kinetically similar to the IgM antibody response, so its detection could be referred to as a recent viral activity. On the other hand, IgG1 and IgG4 were detected in both the convalescent and memory phases of the immune response, but their isolated occurrence without IgG2 and IgG3 could be related to the long-lasting immunity.

[Resurgence of measles in the province of Cordoba, Argentina, in 2000]. / Resurgimiento de sarampión en ia provincia de Córdoba, Argentina, en 2000.

Since 1993, ministers of health of countries of America established as a goal the eradication of measles by the year 2000. As a consequence of measles eradication vaccination strategy there has been a reduction in the incidence of reported cases. Despite that, measles has continued occurring in epidemic outbreaks in many Argentinian provinces. This paper describes and analyzes the outbreak which occurred at Córdoba province, in 2000. Out of 46 serum samples analyzed from suspected cases, 6 (13.3%) were confirmed as measles by indirect immunofluorescence and enzyme immunoassays. All of them were detected in Cordoba city among both without vaccination data and unvaccinated individuals. The epidemiological links among the measles cases could be established although the geographic source of measles importation as well as the primary infection source remain unknown. The highest measles incidence was observed in the group > or = 20 year old (50%), followed by the pre-school age group (< or = 4 year old, 33.3%). The active vaccination data directed against the suspected case contacts along with a high measles population immunity probably contributed to restrict the 2000 outbreak.

Resurgimiento de sarampión en ia provincia de Córdoba, Argentina, en 2000 / [Resurgence of measles in the province of Cordoba, Argentina, in 2000]

Since 1993, ministers of health of countries of America established as a goal the eradication of measles by the year 2000. As a consequence of measles eradication vaccination strategy there has been a reduction in the incidence of reported cases. Despite that, measles has continued occurring in epidemic outbreaks in many Argentinian provinces. This paper describes and analyzes the outbreak which occurred at Córdoba province, in 2000. Out of 46 serum samples analyzed from suspected cases, 6 (13.3

) were confirmed as measles by indirect immunofluorescence and enzyme immunoassays. All of them were detected in Cordoba city among both without vaccination data and unvaccinated individuals. The epidemiological links among the measles cases could be established although the geographic source of measles importation as well as the primary infection source remain unknown. The highest measles incidence was observed in the group > or = 20 year old (50

), followed by the pre-school age group (< or = 4 year old, 33.3

). The active vaccination data directed against the suspected case contacts along with a high measles population immunity probably contributed to restrict the 2000 outbreak.

Resurgimiento de sarampión en ia provincia de Córdoba, Argentina, en 2000. / [Resurgence of measles in the province of Cordoba, Argentina, in 2000]

Since 1993, ministers of health of countries of America established as a goal the eradication of measles by the year 2000. As a consequence of measles eradication vaccination strategy there has been a reduction in the incidence of reported cases. Despite that, measles has continued occurring in epidemic outbreaks in many Argentinian provinces. This paper describes and analyzes the outbreak which occurred at Córdoba province, in 2000. Out of 46 serum samples analyzed from suspected cases, 6 (13.3

) were confirmed as measles by indirect immunofluorescence and enzyme immunoassays. All of them were detected in Cordoba city among both without vaccination data and unvaccinated individuals. The epidemiological links among the measles cases could be established although the geographic source of measles importation as well as the primary infection source remain unknown. The highest measles incidence was observed in the group > or = 20 year old (50

), followed by the pre-school age group (< or = 4 year old, 33.3

). The active vaccination data directed against the suspected case contacts along with a high measles population immunity probably contributed to restrict the 2000 outbreak.

Sequence analysis of measles virus hemagglutinin isolated in Argentina during the 1997-1998 outbreak.

Sequence analysis was performed on 50 measles viruses (MV) isolated in Argentina. Forty-six were obtained during the current outbreak (1997-1998), three from the previous outbreak (1991) and one sporadic case (1994). A 377-bp fragment of the hemagglutinin (H) gene was directly amplified by RT-PCR from nasopharyngeal secretions. Nucleotides 8152 to 8417 were sequenced and subjected to phylogenetic analysis. Multiple silent changes and point mutations were found in all MVs. In 1991, substitutions affected the third base in codons resulting in silent changes. In 1994 an A-->C substitution at position 8321 changed amino acids 351 (Leu-->Ile). In 1997-1998, an A-->G substitution at position 8339 changed amino acids 357 (Val-->Ile). In 3/46 viruses, guanine deletion at position 8205 changed the reading frame and insertion of an extra cytosine at nucleotide 8235 shifted it back to the original frame. Phylogenetic analysis revealed that viruses leading to the last two major outbreaks are clustered into two separate branches. MVs that prevailed until 1994 were related to genotype C1 and MVs of the current outbreak to D6. Random drift mutations rendered a 0.5 ratio of nonsilent over silent mutations in most of the MVs analyzed. However, in those showing a reading frame shift, the ratio was greater than 1, suggesting that it was driven by immune selection.

[Measles outbreak in the province of Córdoba, Argentina, in 1998]. / Brote de sarampión en la provincia de Córdoba, Argentina, en 1998.

The World Health Organization had the global target of reducing reported measles incidence from pre-vaccination era in American countries by 1995, to later eliminate indigenous measles transmission. The countries that have given priority to measles control have substantially reduced morbidity and mortality. Despite that, measles has continued occurring in epidemic outbreaks. This paper describes and analyses the outbreak occurred in Cordoba province, Argentina, in 1998. Out of 195 serum samples analysed from suspected cases, 28 (14.4%) were confirmed as measles by laboratory diagnosis. Of them, 25.0% occurred among vaccinated persons, 39.3% among unvaccinated ones, and 35.7% in individuals without reported vaccine status. The highest measles incidence was in the group aged 20-29 years old (60.7%), followed by the pre-school age group (1-4 years old) (21.4%), the infants under one year of age (14.3%) and finally 3.5% in the group older than 30 years old. These findings suggest a change in measles epidemiology with respect to the pre-vaccine era. The ability to prevent the next epidemic outbreaks will depend on the efficacy to prevent the accumulation of susceptible individuals and the maintenance of high measles vaccine coverage levels.

Brote de sarampión en la provincia de Córdoba, Argentina, en 1998 / Measles outbreak in the province of Córdoba, Argentina, in 1998

The World Health Organization had the global target of reducing reported measles incidence from pre-vaccination era in American countries by 1995, to later eliminate indigenous measles transmission. The countries that have given priority to measles control have substantially reduced morbidity and mortality. Despite that, measles has continued occurring in epidemic outbreaks. This paper describes and analyses the outbreak occurred in Cordoba province, Argentina, in 1998. Out of 195 serum samples analysed from suspected cases, 28 (14.4) were confirmed as measles by laboratory diagnosis. Of them, 25.0 occurred among vaccinated persons, 39.3 among unvaccinated ones, and 35.7 in individuals without reported vaccine status. The highest measles incidence was in the group aged 20-29 years old (60.7), followed by the pre-school age group (1-4 years old) (21.4), the infants under one year of age (14.3) and finally 3.5 in the group older than 30 years old. These findings suggest a change in measles epidemiology with respect to the pre-vaccine era. The ability to prevent the next epidemic outbreaks will depend on the efficacy to prevent the accumulation of susceptible individuals and the maintenance of high measles vaccine coverage levels.

Brote de sarampión en la provincia de Córdoba, Argentina, en 1998 / Measles outbreak in the province of Córdoba, Argentina, in 1998

The World Health Organization had the global target of reducing reported measles incidence from pre-vaccination era in American countries by 1995, to later eliminate indigenous measles transmission. The countries that have given priority to measles control have substantially reduced morbidity and mortality. Despite that, measles has continued occurring in epidemic outbreaks. This paper describes and analyses the outbreak occurred in Cordoba province, Argentina, in 1998. Out of 195 serum samples analysed from suspected cases, 28 (14.4) were confirmed as measles by laboratory diagnosis. Of them, 25.0 occurred among vaccinated persons, 39.3 among unvaccinated ones, and 35.7 in individuals without reported vaccine status. The highest measles incidence was in the group aged 20-29 years old (60.7), followed by the pre-school age group (1-4 years old) (21.4), the infants under one year of age (14.3) and finally 3.5 in the group older than 30 years old. These findings suggest a change in measles epidemiology with respect to the pre-vaccine era. The ability to prevent the next epidemic outbreaks will depend on the efficacy to prevent the accumulation of susceptible individuals and the maintenance of high measles vaccine coverage levels.(AU)

Brote de sarampión en la provincia de Córdoba, Argentina, en 1998. / [Measles outbreak in the province of Córdoba, Argentina, in 1998]

The World Health Organization had the global target of reducing reported measles incidence from pre-vaccination era in American countries by 1995, to later eliminate indigenous measles transmission. The countries that have given priority to measles control have substantially reduced morbidity and mortality. Despite that, measles has continued occurring in epidemic outbreaks. This paper describes and analyses the outbreak occurred in Cordoba province, Argentina, in 1998. Out of 195 serum samples analysed from suspected cases, 28 (14.4

) were confirmed as measles by laboratory diagnosis. Of them, 25.0

occurred among vaccinated persons, 39.3

among unvaccinated ones, and 35.7

in individuals without reported vaccine status. The highest measles incidence was in the group aged 20-29 years old (60.7

), followed by the pre-school age group (1-4 years old) (21.4

), the infants under one year of age (14.3

) and finally 3.5

in the group older than 30 years old. These findings suggest a change in measles epidemiology with respect to the pre-vaccine era. The ability to prevent the next epidemic outbreaks will depend on the efficacy to prevent the accumulation of susceptible individuals and the maintenance of high measles vaccine coverage levels.