An outbreak of coxsackie B-5 virus infection in a newborn nursery

THE JOURNAL OF

PEDIATRICS AUGUST

1966

V o l u m e 69

Number

2

An outbreak of Coxsackie B-5 virus infection in a newborn nursery An outbreak of Coxsackie B-5 virus infection among newborn infants in a maternity hospital is described. The infection was sporadic and mild among full-term infants, whereas the majority of premature infants exposed became infected and ill. The infected infants showed a spectrum of illness from apparent health to manifest aseptic meningitis, but the severe reactions usually associated with Coxsaekie infections in the newborn were absent; there was no clinical evidence of myocarditis. The first cases detected were the result of in utero infections. The majority of infants developed a neutralizing titer to the virus, but some premature infants failed to develop complement-fixing antibodies.

V. J. Brightman, M.D.Se., Ph.D., T. F. McNair Scott, M.D.(Cantab), F.R.C.P.(Lond.),* M. Westphal, M.D., and T. R. Boggs, M.D. PHILADELPHIA~

PA.

not reveal a n y extensive o u t b r e a k of Coxsackie B-5 infection in a nursery for newborn infants, although sporadic infection of v e r y y o u n g infants w i t h this virus has been r e c o r d e d several times. I n these reports, B-5 virus has usually caused a serious a n d often fatal infection similar to t h a t caused by o t h e r types. 4, 0, 6 I n the nursery o u t b r e a k here r e p o r t e d there was no clinical evidence of myocarditis a n d no deaths occurred, r despite clinical manifestations

O U T B R E A K S of Coxsackie B infection have been recognized a m o n g neonates since 1955.1, 2 Several types of virus have been identified in these outbreaks, a n d in most instances the disease has been severe a n d often caused d e a t h of thec:nfant from m y o carditis a n d / o r encephalitis. ~ A fairly extensive review of the literature, however, d i d

From The Children's I-Iospitall of Philadelphia, The Pennsylvania Hospital, and The Department of Pediatrics, School of Medicine, University of Pennsylvania. This study was aid~ed by National Institutes of Health Grant NB-02366 and by National Foundation Grant CR-199.

*One full-term infant (SMI) who showed no evidence of Coxsackie B-5 virus infection in the newborn period subsequently acquired the infection at h o m e a n d died on the thirty-fourth day of life with evidence of pneumonitis, perlcardltls, myocardltls, mad encephalitis. Coxsackie B-5 virus was isolated at autopsy from the lungs, heart, and cerebellum.

*Address, Children's Hospital, 1740 Bainbridge Street, Philadelphia, Pa. 19146.

179

1 80

Brightman et al.

August 1966

of aseptic meningitis in several infants. The outbreak occurred during August and September, 1961, in the nurseries of a large obstetric hospital in Philadelphia and coincided with a period of widesprea d occurrence of Coxsackie B-5 virus infection in the community. By fortunate coincidence, a routine search for viruses infecting newborn infants had been underway for over a year and was being continued during the period of the outbreak. As a result, specimens were being collected routinely from all infants with symptoms, from those with a history of a sick mother, and as controls, f r o m apparently well infants who were born on the same day. In addition, portions of the placentas of all premature infants were being submitted for virologic assay and a number of cord blood and sequential serum specimens from mothers were available. Subsequent testing of these routinely collected materials revealed a much wider spread of infection by Coxsackie B-5 virus than was suspected clinically. ENVIRONMENTAL

BACKGROUND

The nurseries associated with the service were situated on different floors as follows: On the third floor was Nursery 3 which housed full-term (FT) infants born on the ward service; on the sixth floor, Nursery 6 housed full-term infants from the private service; while on the fifth floor, Nursery 5 housed premature (P) infants (2,500 grams or less) from both services. The routine nursery procedures for the nurses included wearing special operating room unifomls with caps, but not masks. They handled the infants without gloves, but hand washing was carried out after the care of each infant. Each infant was treated separately for bathing and changing, and there was no common area for this purpose. Premature babies were handled in Isolettes, incubators, or bassinets according to need. Visiting physicians were required to wear gowns, caps, masks, and gloves. Sick infants were removed to an isolation nursery. However, during the epidemic when no new babies were admitted to the premature nursery, the obviousIy sick

babies were cared for there with special gown and glove technique. LABORATORY

TECHNIQUES

The laboratory data were derived from specimens received as follows: (1) from clinically ill babies; (2) from a survey for evidence of Coxsackie B-5 virus infection carried out on Sept. 1, 1961, ~ among ten premature infants in Nursery 5, only one of whom was recognizably sick on that day, and two full-term babies from Nursery 6, who appeared well; (3) from a routine study to determine the presence of viruses from sick babies and babies with histories of sick mothers and from appropriate controls; (4) from infants available for follow-up; (5) from two nurses from Nursery 5 who had an illness compatible with a Coxsackie infection; and (6) from nine mothers and seven other relatives of sick babies. Specimens for virus isolation (throat swab, rectal swab, eerebrospinal fluid, and placental tissue obtained at delivery) were collected by standard procedures and immediately frozen in dry ice until used. For virus isolation, each specimen was routinely inoculated into suckling mice and into 4 tubes of primary monkey kidney ( M K ) , HeLa, a n d / or HEp-2 cells. The virus grew well and produced characteristic pathologic lesions or characteristic cytopathic effect in all these hosts, but culture line cells (either H e L a or HEp-2) were the most effective hosts. All virus isolates, regardless of the host in which they were isolated, were identified on M K cells and neutralized by a standard commercialt Coxsackie B-5 antiserum on this host. Sera from either cord or venous blood were tested as follows: for the presence of complement-fixing antibody$ to a Freonized H e L a cell culture of a standard strain of Coxsackie B-5 virus, and for the presence of neutralizing antibody to the same virus strain. ~The first report of the presence of Coxsackie t/-5 virus was made August 31, 1961. tMierobiological Associates, Washington, I3. C. :)These tests were performed by the Virus Diagnostic Laboratory of the Commottwealth of Pennsylvania, and by Dr. John Sever, National Institutes of Health.

Volume 69 Number 2

RESULTS

Description of the outbreak. When all the data were available, it was possible in retrospect to define two separate incidents. One consisted of two sporadic cases of Coxsackie B-5 infection in the full-term Nursery 3: an asymptomatic infant ( M O T ) , ~ who was found to be excreting virus on the third day of life (Aug. 14, 1961), and BAI, who developed Coxsackie B-5 aseptic meningitis on August 18. The other, apparently separate epidemic involved Nurseries 5 and 6, and was traced back to August 13. Placental tissue obtained at the birth of an asymptomatic premature infant (WHA) on that day was in retrospect shown to contain the virus, this being the earliest specimen in the study from which the virus was isolated. The presence of Coxsackie B-5 infection in these two Nurseries 5 and 6, however, was not suspected until August 30, when the isolation and identification of Coxsackie B-5 virus from the spinal fluid of BAI was reported. Nursery 5 was closed at this time and Nursery 6 closed the next day. This outbreak involving Nurseries 5 and 6 was finally considered ended on September 11, 1961, when the last infant known to have been infected while in these two nurseries (PAO[A]) ~ was discharged. Nurser 7 3 was never closed to new admissions, as any sick infant was isolated as soon as his illness was recognized. Illness recognized among infants and staff at the time of the outbreak. The retrospec, tire summary of the outbreak and the details which follow present quite a different pattern from the sequence of events observed at the time the outbreak was occurring. Thus in Nursery 3, only 2 infants ( S M I t and BAI) were recognized as being sick during the period of the outbreak. In Nursery" 5, an ll-day-old premature infant (SAB) showed a failure of weight gain on August 23 and was isolated because of a febrile illness from "XAli infants w e r e assigned 3 letter code names which are used throughout this report. (M) indicates the in[ants' mother, (A) and (B) indicate twins. "~SMI became sick on August 13, with unexplained fever. In view of negative cultujies she w~/s not Considered to be infected with Coxsackie B-5 virus a t this time. She subsequently developed a fatal viral infection after discharge. See previous footnote concerning SMI.

Coxsackie B-5 outb.reak in nursery

18 1

August 26 to September 2. No other infants were observed to be sick in this nursery up until the time it was closed on August 30, but two nurses ( C O T and CAS) working in the nursery developed severe chest pain and fever on August 20 and August 24, respectively, and were sent off duty from August 24 to August 27 and from August 26 to August 29, respectively. In Nursery 6, 4 infants were observed to be sick: G R I (B) and PAO (A), premature infants transferred from Nursery 5 on August 27 because of satisfactory weight gain, each had a febrile illness of 3 days' duration shortly after transfer to this nursery; and SOD and FOG, fullterm infants housed in this nursery since birth, also experienced similar illness at this time. Retrospective analysis of the outbreak. The histories of all the infants who had been present in the three nurseries between August 3 and September 11 were reviewed for evidence of illness. This information was supplemented with the results of virus isolations and serologic tests carried out on the specimens described under Laboratory Techniques, and the following details of the outbreak were reconstructed: as illustrated in Table I and Fig. 1, Coxsackie B-5 virus was found in each of the 3 nurseries. Nursery 3. Among 143 infants passing through this nursery between Aug. 3 and Sept. 11, 1961, only 2 infected infants were found ( M O T and BAI). The first infection appears to have occurred in M O T who was not sick. From this "control ''~ infant, born Aug. 11, 1961, and discharged August 18, routine rectal and throat swabs were taken on August 14. Coxsackie B-5 virus was isolated from the rectal swab but not from the throat swab, and the neutralizing antibody titer was 256 on the thirty-eighth day of life in contrast to the lack of titer in the mother's blood taken at time of delivery (Table I I I ) . Unfortunately, no follow-up data were obtained from the mother. T h e presence of CAn asymptomatic infant from w h o m rectal and throat swabs for virus iso!ation were taken as a control for comparison with those taken f r o m S M I , sick with an unexpla!ned fever Aug. 13 to Aug. 15, 1961, (Newborn Virus Study).

1 82

Brightman

August 1966

et al.

Table I. Summary of all infants in the three nurseries, Aug. 3 to Sept. 11, 1961

Nursery identification

Total n o . Of babies

Premature No. Full-term No. Full-term No.

21 143 10

Injected with Coxsackie B-5 Sick ~

Not sick

11"~ 1 1

3t 1 0

Not injected with Coxsackie B-5 Sick ~

1w t82 1~

No laboratory tests [or Coxsackie B-5

Not sick

Sick at home

Not sick

311 6# 2

0 7 0

3 127 6

*Defined on retrospective review, although not necessarily considered clinically significant at the time. t(GRI[A]) had high antibody to Coxsackie B-5 in the convalescent serum. :~(PAG) by rise in antibody to Coxsackle B-5 only, probably infected at home. w (1,430 grams at death), no virus isolated from placenta. No postmortem virus isolations undertaken; acute bilateral bronchopneumonia and acute omphalitis (E. coll cultured from lungs). IlThree placentas tested, no virus isolated. [[(SMI) no virus isolated in hospital; later infected with Coxsackie B-5 at home. # O n e had high neutralizing antibody to Coxsackie B-5 in cord blood. Placentas of 2 only tested; no virus isolated. **(FOG) no virus isolated quent test possible.

during illness. Serum taken fifth day negative for antibody to Coxsackie B-5; no subse-

virus in the rectal swab on the third day of life, however, is suggestive of an infection acquired in utero. The second infection occurred in BAI, born Aug. 14, 1961, who developed aseptic meningitis on August 18, at which time she was removed to a separate isolation unit. It is possible that this infant was infected from M O T but evidence to be discussed later (Results of Serologic Tests) suggests that an intrauterine infection is more probable. There were 38 infants in this Nursery between August 11 and August 18 inclusive, who were thus potentially exposed to either or both of these infants (Fig. 1). No evidence of B-5 infection was found in one sick infant (SMI), or in 2 asymptomatic infants tested at the same time. Twenty-six of these 38 infants were followed and only 7 of them had illnesses within 3 weeks of discharge which could possibly have been caused by Coxsackie B-5 virus (5 with colds and 2 with diarrhea). N u r s e r y 6. G R I (B), a premature twin, who graduated from the premature Nursery 5, where infection was prevalent, to Nursery 6 on August 27, became ill with a fever of 101.2 ~ F. on August 30 and was immediately isolated. Spinal fluid taken that day showed a pleocytosis and subsequently yielded Coxsackie B-5 virus on culture. On the same day, a full-term infant (FOG) became sick with fever of 100.6 ~ F. and a full fontanelle.

Spinal puncture yielded bloody fluid which was bacteriologically sterile and from which no virus was isolated; throat and rectal swabs were also negative, and no antibodies were detectable on discharge (fifth day). Although no further serologic follow-up was possible, it is unlikely that this child was suffering from Coxsackie B-5 infection. Exposed to these 2 infants were 9 full-term infants and one other premature (PAO[A]) who had also been transferred to Nursery 6 on August 27. On August 30, SOD, one of the full-term infants, became sick but recovered in 3 days. The spinal fluid contained only 7 cells per cubic millimeter, but subsequently yielded Coxsackie B-5 virus on culture, the same virus being isolated from a rectal swab. Since there was no later serologic evidence that the mother had been infected, it is probable that SOD's infection was derived from GRI(B) after a 2 day incubation period. The other transferred premature (PAO[A]) became ill on September 3 and Coxsackie B-5 virus was isolated from throat and rectal swabs, but not from spinal fluid taken at this time. This infection could have been contracted in Nursery 5 with an incubation period of 7 days or longer, or from G R I (B) or SOD after transfer to Nursery 6, with an incubation period of 3 to 7 days. There was no evidence of infection in the remaining 8 full-term infants who were

Volume 69 Number 2

NURSERY

CoxsaCkie B-5 outbreak in nursery

1 83

:3

INFECTED

~40T BAI (8/11) 8/18

SICK AT HOME ?INFECTED IN HOSPITAL

NO FOLILOW-UP

CONTACTS NOT INFECTED

NURSERY 5 INFECTED NOT SICK

WEL WHA (8/11}

INFECTEDSICK

(8/13}

[WIL

WESt I

8/18 INFECTED AFTER TRANSFER TO NURSERY 6 , 8 / 2 7

INFECTED AT HOME

r~

SAN ICHA CARI lOON HAMI WAR GRllA) I

8/25 ~.

8/24

I

8/25

8/28

8/31

~ [SEE ALSO NURSERY 6]

GRI(B) PAO(A)

PAG

NOT INFECTED DIED

NURSERY

6 9

9

INFECTED

NURSERY 6

8/27 l

GRI(B) PAO(A) SOD 8150 915 8/31

NOT INFECTED

FOG 8130

KEY

Fig. 1. Infants infected with Coxsackie B-5 virus and infants in contact with them in the three nurseries; Aug. 3 to Sept. 11, 1961. asymptomatic. I n 2 of them throat and rectal swabs were found .to be negative for Coxsackie B-5 infeetion and no further follow-up history was obtained; the remaining 6 were

not tested, but a follow-up history of these revealed no clinical illness. Thus of a population of 153 full-term infants in Nurseries 3 and 6, only 3 ( M O T ,

1 84

Brightrnan et al.

BAI, and SOD) had laboratory confirmed Coxsackie infection. Of the remaining 150 infants, two were sick from other causes (SMI, F O G ) , and 148 were clinically well in the hospital although 7 suffered mild illness on returning home, which may have resulted from hospital acquired infection. The lack of spread of infection among the exposed full-term infants in either of these two nurseries is in contrast to what occurred in the premature nursery. Nursery 5. Fourteen of the 21 premature infants admitted to this nursery from Aug. 3, t961, until it was closed to new admissions on August 30 were proved to have had Coxsackie B-5 infection (Tables I I and I I I ) . Of these, 11 had symptoms of greater or lesser degree and 3 (WHA, WEL, and PAG) were asymptomatic as judged by a retrospective review of records. Nine developed clinical illness while in Nursery 5,* and 2 ( G R I [ B ] and PAO [A] ) developed symptoms only after transfer to Nursery 6. Two of the asymptomatic group ( W H A and WEL) were excreting virus in the hospital, diagnosis in the third (PAG) was made only by a rise in neutralizing antibody to Coxsackie B-5 virus, detected on the forty-sixth day after discharge, which could have been due to infection acquired at home. Her mother (PAG [M]) showed a rise of both complementfixing and neutral~ing antibodies in the same period (Table I I I ) . The 7 remaining infants were not considered to be infected: one of these died on the seventh day of life of Escherichia coli bronchopneumonia, but" no virus was isolated from the placenta. The postmortem tissue was not tested. The earliest virus isolation in Nursery 5 was from the placenta of an asymptomatic infant (WHA) on August 13, 1961, which suggests an intrauterine infection (see later discussion). This infant was not sick and no special precautions were taken, but he was apparently infective throughout his stay since *Eight of the 9 p r e m a t u r e infants judged to be symptomatic by retrospective review of records became " i l l " prim" to the recognition of Coxsackie B-5 infection in Nursery 3 a n d the closing of Nursery 5 o.rL Aug. 30, 1961. O f these, only one (SAB) had symptoms which were sufficiently striking at the time to w a r r a n t isoIation of the ~nfant.

August 1966

virus was found in his feces on August 31, tile eighteenth day of life. The other asymptomatic infant (WEL) was admitted 2 days before W H A and was found to. be excreting virus on the twenty-first day of life when a culture was taken during the survey on September 1, at which time he had developed a high titer of neutralizing antibodies. His mother ( W E L [ M ] ) showed no serologic evidence of infection although followed for 5 months. It seems certain that he acquired his infection in the nursery, probably not later than August 25, since the earliest t i m e at which a comparable titer of neutralizing antibody was produced by premature infants (CHA, H A M ) was the seventh day after onset of illness (Table I I I ) . Subsequent infections in this nursery are illustrated in Fig. 2. It will be seen that if the infected infants are plotted according to the time of their illnesses or known infection, it would appear that W H A was the first infected infant and probably the original source of infection in Nursery 5. The two nurses, C O T and CAS, who were sick while on duty may have been infected from the infants, although infection from the outside cannot be excluded. On the third and fourth days after the onset of symptoms in Nurse C O T , 5 infants became infected, possibly from this nurse. No virus isolation tests were attempted on these nurses during their acute illness. Evidence of infection rests on clinical illness and the presence of high titer of antibody in the convalescent sera. Incubation period. It was not possible to determine this accurately; however, two periods could be defined. SOD became infected on the second day of life; the second case (WIL) in Nursery 5 occurred 5 days after the admission of the source infant (WHA). Symptomatology. The symptoms of the infants infected in the nursery varied from those of a subclinical infection, through failure to gain weight, up to a classical picture of aseptic meningitis (Table I I ) . No clinical evidence of myocarditis was noted (routine electrocardiograms were not taken). Relation of virus isolation to illness. Virus was isolated from 12 of the t3 infants clini-

Volume 69

Number 2

Coxsackie B-5 o u t b r e a k in nursery

18 5

T a b l e I I . C l i n i c a l a n d l a b o r a t o r y f i n d i n g s in 15 i n f a n t s f r o m w h o m C o x s a c k i e B-5 v i r u s w a s i s o l a t e d

Infant's name BAI

Genera~ symptoms

Fever Anorexia

Gastrointestinal symptoms None

. Coxsackie B-5 virus isolation ~ Nervous symptoms

Cerebrospinal fluid (CSF)

Lethargy

None

Placenta

Throat Rectum

NT

NT

NT

NT

NT

+++

++4

q-~ +

CAR

Weight plateau Vomited Not vigorous Poor skin color

None

None

NT

+

CHA

Weight plateau None

None

None

-

-

GRI (B)

Fever None Weight plateau

Lethargy

180 cells/c.mm. 75% lymphocytes

HAM

Weight plateau None

None

None

-

-

JOH

Weight plateau None

Lethargy One convulsion

35 cells/c.mm. 80% lymphocytes

-

+

MOT

None

None

None

NT

++4

++4

None

NT

-

PAO (A)

Anorexia None Weight plateau Fever

None

Red blood cells only

SAB

Anorexia None Fever Weight plateau

Lethargy

170 cells/c.mm. 52% polymorphonuclear leukocytes

NT

SOD

Fever Anorexia

Irritable

7 white blood cells/ c.mm. 677 red blood ceils/ c.mm. Sugar 57 rag. %

NT

WAR

Anorexia Diarrhea Weight plateau

Lethargy

None

NT

WEL

None

None

None

None

-

WES

Weight loss

None

Lethargy

1-2 cells per slide Sugar 92 rag. %

WHA

None

None

None

None None

Diarrhea

CSF

(1) 1090 cells/c.mm. 95 % polymorphonuclear leukocytes (2) 85 cells/e.mm. .34% polymorphonuclear leukoeytes Sugar 48 rag. %

+++

-

NT

+

NT

++§

+

-t-+

Nrl"

NT

NT

++4

+

NT

NT

+

§

+++

+++

NT

-

+

NT

+++

+++

NT

+++

--

+

NT

NT

+

+

NT

NT

WIL Weight plateau None None ~Amount of virus present roughly estimated bu the basis of ease of isolation in tissue culture; +++ ~ cytopathogenic effect (CPE) on original culture in the less sensitive monkey kidney celIs; ++ ~ CPE on first passage in the less sensitive monkey kidney cells; + z CPE on first passage in the sensitive cells (HEp-2 and HeLa) o n l y ; - - ~ no CPE; NT ~- not tested.

catly ill f r o m t h e i n f e c t i o n . I n 7 t h e v i r u s

10 d a y s a f t e r t h e e n d of thei~ illness. V i r u s

was i s o l a t e d d u r i n g t h e c o u r s e of t h e i r illness as j u d g e d b y i m m e d i a t e c l i n i c a l o b -

w a s still f o u n d i n t h e t h r o a t o f o n e i n f a n t

s e r v a t i o n o r r e t r o s p e c t i v e a n a l y s i s of t h e r e c -

t h e o n s e t o f illness a n d d e s p i t e t h e p r e s e n c e

ords; in 5 t h e v i r u s w a s i s o l a t e d f r o m 1 t o

of c i r c u l a t i n g a n t i b o d y ; b u t n o v i r u s w a s iso-

( W E S ) as l a t e as t h e f o r t y - f o u r t h d a y a f t e r

1 86

Brightrnan et al,

August 1966

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Volume 69

Number 2

Coxsackie B-5 outbreak in nursery

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E v

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r V

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1 88

Brightman et al.

August 1966

=E IZ bJ

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PAO (A}

2360

GRI (A) 2270 GRI(B)

2300

WAR

1560

HAM

IBaO I

JOH

1570

CHA

1930

CAR

1480

CAS

NURSE

SAB

2250

COT

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WES

2211

WlL

1270

WHA

1820

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1440 I I I I I August 5

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MOVED TO NURSERY 6

I I I 15

I I I I i 20

I I I I I I I t I I I I I I I I 25 30 September 5

I J I I I I0

I I I I I I 15

8/27/61

Fig. 2. Hospital course of the 13 premature infants infected in the hospitaI, plotted according to the date of onset of illness, or of birth if asymptomatic (WEL, WHA). Number preceding illness is age of infant at onset in days. Arrow indicates date of virus isolation in hospital, arrow in brackets, date of virus isolation at home. COT and CAS were nurses assigned to premature nursery for period indicated and ill with Coxsackie infection during this period.

lated in 3 others on the fortieth, forty-second, and fifty-fifth days or in 8 tests on 6 patients after the fifty-fifth day. Results of serologic tests. Table I I I summarizes the complement fixing (CF) and neutralizing titers of 15 infants from w h o m the virus was isolated while in the hospital, 1 infant from w h o m no virus was isolated but who showed an antibody rise and probably was infected at home ( P A G ) , and 1 infant ( G R I [ A ] ) , the twin of an infected infant, who showed a high neutralizing titer equal to that of her sister when tested at 5 months. Where available, titers from the mothers' sera are also tabulated. T h e following points are noteworthy: Development of antibodies. All but 2 ( W I L , SOD) of 17 infected infants developed either neutralizing a n d / o r CF antibodies against the standard strain of Coxsackie B-5 virus. Six premature infants

(CHA, G R I [ B ] , J O H , W A R , WES, P A G ) failed to develop CF antibody after an adequate period of follow-up, although they did develop neutralizing antibody. Regarding the 2 infants who failed to develop either antibody: W I L , a sick premature baby, was followed only for 2 weeks and may have developed antibody later. SOD, a full-term infant with clinical meningoencephalitis, deserves c o m m e n t : T w o days after birth, on the day of onset of the illness, S O D had a CF titer of 32 and a neutralizing titer of < 4 , paralleling the titers of 64 a n d 10, respectively, in the mother. Despite the strong evidence for infection, based on the isolation of virus from the spinal fluid and the rectal swab, this infant had developed neither neutralizing nor CF antibodies when tested at 56 days and 7 months. Rate of antibody formation. Whereas most of the infants had definite rises of neutral-

Volume 69 Number 2

izing antibody detectable between 30 and 90 days, 1 small premature (WAR, 1,560 grams) had very little neutralizing antibody (8) by the forty-first day but eventually developed a high titer (512) by the hundred and thirteenth day. In contrast, 3 premature infants (HAM, 1,820 grams, CHA, 1,930 grams, and PAO[A], 2,360 grams) had high titers as early as the seventh ( H A M ) , eighth, (CHA) and second days (PAO[A]) after onset of their illness. Each of these infants had been exposed to infection for 22, 18, and 12 days, respectively, before the onset of clinical illness and it seems probable that infection preceded recognition by several days. Although possible, it seems unlikely that a neutralizing titer of 64 in PAO(A), 2 days after onset of symptoms, was passively transmitted, since such a high titer of neutralizing antibody should have protected the infant. Maternal antibodies. Seven of the mothers (CHA[M], H A M [ M ] , J O H [ M ] , WAR[M], WEL[ g ], WES [ M ], SOD [ M ] ), apparently never developed Coxsackie B-5 infection, although 3 (CHA[M], WES[M], and SOD[M]) had CF antibody to this virus the titer of which did not change significantly with time. These findings are compatible with the wellknown heterologous cross reaction from a previous enterovirus infection of some other type. One mother, G R I ( M ) , had a lower titer of neutralizing antibody than her proved hospital-infected premature infant (GRI[B]) when she was tested on the eighty-third day after the onset of thi~ infant's illness and the seventy-seventh day after returning home. Since her titer continued to rise to the fifth month, at which time the infant's titer had started to decline, it seems probable that she could have been infected .from her infant, although she complained of no significant symptoms. Mother SAB(M) also may have been infected at home, because, when tested on the sixty-sixth day after onset of the baby's illness (53 days after the infant's arrival home), she had a much lower titer than her infant who was infected in the hospital. Two mothers, BAI(M) and W H A ( M ) , deserve special comment: BAI(M) had a

Coxsaekie B-5 outbreak in nursery

18 9

tubal ligation immediately after delivery on August 14. She developed a transient rise of temperature to 102.6 ~ F. on August 16, but no other symptoms. It can be assumed from the infant's titer on the fourth day after onset of illness that the mother's neutralizing antibody titer at delivery was 4 or less; by the sixth day after onset of the infant's illness, the mother's titer had risen to 40, and by the sixty-third day to 620. The contrastingly high CF titer found on the sixth day after onset of the infant's illness, which was unchanged on the sixtythird day, can be assumed to be the result of an infection by another enterovirus sometime in the past. Subsequent investigation of the family revealed that this mother could have been infected 5 to 7 days before delivery from caring for her two youngest children who were suffering from an illness compatible with a Coxsackie B-5 virus infection at that time. The transient fever on August 16 could have been a manifestation of this infection, which was incubating during the period immediately prior to delivery and which was passed to her infant in utero or shortly post partum, to account for the infant's aseptic meningitis on the fourth day of life. In mother W H A ( M ) , the evidence of intrauterine infection is even stronger. This woman, in the thirty-seventh week of her pregnancy, complained of generalized lower abdominal pain for 2 days, her temperature was 100 ~ F. and she had 25 to 30 white blood cells per high power field in her urine. There was no evidence of onset of labor. Acute pyelonephritis was diagnosed and she was given sulfisoxazole,~" although the symptoms were compatible, in retrospect, with a Coxsackie virus infection. In addition, a further study of her history revealed that she had had a urinalysis on a previous visit w i t h similar findings without accompanying pain and fever. On the following day, she was admitted in the second stage of labor and, with the usual sterile precautions, was delivered of a premature infant weighing 1,820 grams. Prior sera from this mother, *Gantrlsln, Roche Laboratories.

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taken 5 and 6 months before delivery, and the cord blood of the infant showed negligible neutralizing titers against Coxsackie B-5 virus. Both the infant, who was found to be excreting virus in the feces on the eighteenth day of life, and the mother, showed a parallel rise of both CF and neutralizing antibodies by the forty-seventh day, and there seems little doubt that this mother had a Coxsackie infection immediately preceding delivery. Because this infant was premature, a portion of the placenta was removed for routine testing. This was given a laboratory code number and tested with 26 other placentas. Only the placenta of W H A was positive for Coxsackie B-5 virus, the virus being recovered on two separate occasions. From the dilution factor it was calculated that there were 50 IDa0 ( M K ) units of virus per gram of tissue. Despite the presence of virus, no histologic abnormalities were detected either in the routine or the retrospective examination of a section of placenta. The unexpected finding of the virus in this amount along with the serologic evidence strongly suggests that the virus was in the placenta at the time of the delivery and that the infant was subclinically infected from this source. A very unlikely alternative possibility exists, which would hardly account for the amount found in the tissue, namely, that the placenta was contaminated as it passed over the perineum of the infected mother, and her infant, who was immediately isolated because of his prematurity, would then have become infected in Nursery 5 where infection later became prevalent. DISCUSSION

An analysis of this epidemic suggests an explanation for the dearth of reports of epidemics of this virus among newborn infants in obstetrical nurseries. In reality the disease on this occasion appeared as an epidemic among the premature infants and as a sporadic infection among the full-term infants. Without the chance association of the "newborn virus" study, it is doubtful if the presence of an epidemic would have been

August 1966

recognized. Of the 3 full-term infants who were infected, the 2 recognizably sick, (BAI) with meningitis and (SOD) with fever and irritability, were admitted to different wards. If the 7 infants who were sick at home were considered infected, their symptoms were so mild and nonspecific that they would certainly not have been considered to be connected with the single case of meningitis. Among the 12 premature infants in whom infection was based on confirmed laboratory data, lumbar puncture was indicated in only 5 ( G R I [ B ] , J O H , PAO[A], SAB, and WES); the others had nonspecific symptoms such as diarrhea and failure to gain weight. The increased incidence of infection among this population of premature infants, despite the routinely introduced precautions, suggests an increased susceptibility to infection. On the other hand, the prolonged hospitalization of premature infants can increase their risk of exposure. It appears that the source of the epidemic among the premature infants was an asymptomatic infant who had been infected in utero (WHA). Of all known infected premature infants, the only one in the ward, when W H A was admitted, was W E L who remained asymptomatic despite the finding of virus in the stools on the twenty-first day of life. Since his mother showed no laboratory evidence of infection, a ward infection must be assumed. If W H A can be taken as the source, the virus appeared to spread from one infant to another in a horizontal fashion. A possible vertical spread to the 2 nurses also m a y have taken place, although an outside source for their infection cannot be excluded. In utero infection by Coxsackie B viruses including B-5 has been suspected from circumstantial evidence. 4, 8 The experience with BAI and W H A reported here is similar, but in the case of W H A the evidence is strengthened by the isolation of the virus from the placenta during a routine test of placentas from premature infants. The absence of pathologic changes in sections of this placenta raises the possibility that it was accidentally contaminated or that virus was iso-

Volume 69

Number 2

lated largely from blood trapped in the tissue. However, it is of interest to note that other investigators 4, 9 have reported isolation of Coxsackie virus in high titer from other tissues which failed to show microscopic evidence of infection. T h e lack of illness in the infant ( W H A ) with in utero infection is unusual since most reported in utero infections have caused severe illnesses which often resulted in d e a t h ? T h e available evidence suggests that the fetus is only liable to be infected by Coxsackie B viruses when the m o t h e r is ill shortly before delivery? ~ This is in contrast to the findings in Rubella virus infection in which infection early in pregn a n c y leads to a persistent infection lasting for months after birth. 11 T h e variability in the development of antibodies by newborn infants was well illustrated by this epidemic. There was no consistent parallelism between the development of C F and neutralizing antibodies in this series of infants, although CF and neutralizing antibodies usually develop coincidentally against Coxsackie viruses in individuals over 2 years of age? 2 T h e development of C F antibody was slower than that of neutralizing antibody and was absent in some instances. A similar delay was noted by K u wert and Lennartz ~3 and by DSm6k. 1. T h e failure to develop either C F or neutralizing antibodies by one of our patients ( S O D ) was surprising but unexplained. SUMMARY

An outbreak of Coxsackie B-5 virus infection occurring a m o n g newborn infants in a maternity hospital has been described. The outbreak occurred at the peak incidence of an epidemic in the community. T h e infection was sporadic a m o n g full-term infants causing 3 proved and 7 possible infections among 35 investigated infants. I n contrast there was proved infection a m o n g 14 of 21 premature infants. T h e first cases detected in both the full-term and the premature nurseries appeared t o be the result of in utero infections, the mothers being infected shortly before delivery. T h e first patient in the premature nursery had a subclinical in-

Coxsackie B-5 outbreak in nursery

19 1

fection despite the demonstration of virus in the placenta. It is probable t h a t the outbreak would have gone unrecognized if a study of virus diseases of the newborn had not been currently underway. Although the infected infants showed a spectrum of illness from apparent health to manifest aseptic meningitis, there was a striking absence of the severe reactions usually associated with Coxsackie infection in the newborn, a n d all patients with aseptic meningitis in the newborn nursery recovered; there was no clinical evidence of myocarditis. T h e antibody response tended to be slow, but eventually 15 of 17 infants developed a neutralizing titer, although 6 prematures failed to develop CF antibody. Tissue culture line cells ( H e L a or H E p - 2 ) were the most effective hosts for isolation of virus. The technical assistance of M. Starzinski, R.N., Gloria Stanton, and Marcia Grim, B.S., is gratefully acknowledged. REFERENCES

1. Montgomery, J., Gear, J., Prinsloo, F. R., Kahn, M., and Kirsch, Z. G.: Myocarditis of the newborn. An outbreak in a maternity home in Southern Rhodesia associated with Coxsackie group-B virus infection, South African M. J. 29: 608, 1955. 2. Javett, S. N., Heymann, S., Mundel, B., Pepler, W. J., Lurie, H. I., Gear, J., Measroch, Veronica, and Kirsch, Z.: Myocarditis in the newborn infant. A study of an outbreak associated with Coxsackie group B virus infection in a maternity home in Johannesburg, J. PEDIAT.48: 1, I956. 3. Rose, Harry M., editor: Viral Infections of Infancy and Childhood, New York, 1960, Paul B. Hoeber, Inc., pp. 27-28. 4. McLean, D. M., Donohue, W. L., Snelling, C. E., and Wyllie, J. C.: Coxsackie B5 virus as a cause of neonatal encephalitis and myocardifis, Canad. M. A. J. 85: 1046, 1961. 5. Schenck, W., Vivell, O., Luthardt, T., and Maas, G.: Eine Epidemie durch Coxsackie-Virus typ B5 auf einer Neugeborenen--und Siiuglingsstation, Arch. Kinderh. 170: 41, 1964. 6. yon Koch, F., Enders-Ruckle, G., and Wokittel, E.: Coxsackie B5--Infektionen mit signifikanter AntikSrberentwicklung bei Neugeborenen, Arch, Kinderh. 165: 245, 1962. 7. Lennette, E. H., and Schmidt, N. J., editors: Diagnostic procedures for viral and rickettsial diseases, New York, 1964, American Public Health Association, Inc., p. 50. 8. Kibrick, S., and Benirschke, K.: Severe gen-

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eralized disease (encephalo hepato myocarditis) occurring in the newborn period and due to infection with Coxsackie virus group B; evidence of intrauterine infection with this agent, Pediatrics 22: 857, 1958. 9. Gold, E., Carvery, D . H., Heineberg, Hannelore, Adelson, L., and Robbins, F. C.: Viral infection. A possible cause of sudden death in infants, New England J. Med. 264: 53, 1961. 10. Plager, Hildegard, Beebe, R., and Miller, J. K.: Coxsackie B5 pericarditis in pregnancy, Arch. Int. Med. 110: 735, 1962.

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11. Rudolph, A. J., Yow, Martha D., Phillips, C. A., Desmond, Murdena M., Blattner, R. J., and Melnick, J. L.: Transplacental Rubella infection in newly born infants, J. A. M. A. 191: 843, 1965. 12. Hammon, W. McD.: personal communication. 13. Kuwert, E., and Lennartz, H.: Untersuchungen mit der Komplementbindungs reaktion anl~isslich einer Coxsackie B5-Epidemie. Klin. Wchnschr. 41: 809, 1963. 14. D6m6k, I.: Virological aspects of Coxsackie virus infections, Arch ges. Virusforsch 13: 128, 1963.