POSSIBLE CONGENITAL LA CROSSE ENCEPHALITIS VIRUS INFECTION
La Crosse encephalitis virus (LACV), a bunyavirus of the California encephalitis serogroup, is a common cause of encephalitis in the United States every year. Most infected patients are asymptomatic. In August 2006 a 46-year-old woman developed LACV infection in the 21st week of pregnancy manifested by severe headaches, photophobia, stiff neck, fever, weakness, confusion and a red papular rash (MMWR 2009;58;4). The diagnosis was established by positive LACV IgM antibody using enzyme-linked immunosorbent and immunofluourescent assays. She recovered uneventfully and the infant was born at 40 weeks gestation and was completely normal during 6 month follow-up evaluations. The umbilical cord serum had a positive LACV IgM by enzyme-linked immunosorbent assay and a positive plaque-reduction neutralization test. The mother had a positive LACV IgG and negative IgM tests 11 weeks postpartum. It cannot be certain that congenital LACV infection occurred, but it appears likely by serologic testing.
ADVICE FROM BEN FRANKLIN
No one disputes the sagacity of Ben Franklin. We grew up on the wise sayings from Poor Richard’s Almanack. In his autobiography is the following brief paragraph: In 1736 I lost one of my Sons, a fine Boy of 4 Years old, by the Small Pox taken in the common way. I long regretted bitterly & still regret that I had not given it to him by Inoculation; This I mention for the Sake of Parents, who omit that Operation on the Supposition that they should never forgive themselves if a Child died under it; my Example showing that the Regret may be the same either way, and that therefore the safer should be chosen. Parents who have qualms about adverse reactions from immunizations might consider this advice concerning regrets about consequences of immunization versus the disease itself and choose the safer way, namely immunization, as Ben wished he had.
Each year in Dallas, Texas we treat several children with malaria. The typical story is that of a family going to visit relatives in equatorial Africa and not taking prophylactic drugs. For that reason we were interested in the study headed by Stäger, Steffan and Schlagenhauf from Zurich on imported malaria in children (≤18 years) of 11 industrialized nations: Australia, Denmark, France, Germany, Italy, Japan, the Netherlands, Sweden, Switzerland, the United Kingdom and the United States (Emerg Infect Dis 2009;15:185). They evaluated 17,009 cases from the 11-year period, 1992–2002. France led the list with 6,618 cases followed by the United Kingdom (3,816), the United States (2,614), Australia (1,504) and Germany (757). Thirty-one percent were children 5 years of age or younger. More than 75% of infections were acquired in Africa and Plasmodium falciparum accounted for 70% of all cases. Based on data from the United Nations World Tourism Organization, they extrapolated from total numbers of visitors to malaria-endemic countries to obtain risk data. For example, French children visiting high risk African countries had an overall risk of 110 cases per 10,000 arrivals, but there was huge variation: 1,030/10,000 for Comoros Islands and 778/10,000 for Congo, but only 3.8/10,000 for Kenya. We applaud the investigators for the tremendous amount of work involved in compiling these data. The perspective they provide helps physicians counsel travelers about prophylaxis for malaria.
MULTIPLE RESPIRATORY VIRUSES
The virus hunters in Turku, Finland continue to provide us with interesting information about respiratory viruses. The latest report is about respiratory viruses in 194 children <4 years of age with acute common cold symptoms without otitis media or other symptoms (Emerg Infect Dis 2009;15:344). By PCR they looked for the following: rhinovirus, respiratory syncytial virus, influenza, para-influenza, adenovirus, human metapneumovirus, human bocavirus, picornaviruses and coronavirus. They found one or more of these viruses in 92% of children. It is no surprise that rhinovirus was identified in 78% of the children. It is surprising that 28% had 2 viruses, 7 children had 3 viruses and 3 children had 4 viruses in a single nasopharyngeal aspirate specimen. Two viruses are easily explainable by sequential infection with the first virus hanging around after the second was acquired, but how do you explain 4 viruses? And which one (or more) is/are causing the symptoms at the time of testing? Are some transient carriers not causing disease? Clinical studies often lead to more question than answers.
INFLUENZA AND THE SINUSES
In a recent 2 week period we managed 5 patients with frontal epidural abscesses and one patient with an intraorbital abscess. All were older children or adolescents who had frontal sinus involvement. Influenza A infection (H1N1) was documented by PCR in 3 patients; in the others the initial upper respiratory infection was more than 7 days before admission. Four patients had Streptococcus milleri group recovered from cultures of surgically drained pus; the others had received previous therapy and had Gram positive cocci in pairs observed on Gram stained smears of purulent material. We treated these patients initially with intravenously administered clindamycin and ceftriaxone until identification of the pathogen. Total therapy was for a minimum of 3 weeks, part of which was given on an ambulatory basis. All the patients did well because of coordinated management with neurosurgery or ophthamology.
EXPANDED PNEUMOCOCCAL VACCINE
The new 13 valent pneumococcal conjugate vaccine from Wyeth Laboratories is on the Food and Drug Administration’s fast-track status. It was recently evaluated in 600 infants who received either this vaccine or the currently licensed 7 valent vaccine (Prevnar®, Wyeth) to determine the immunogenicity of the original 7 serotypes and more importantly of the 6 added serotypes (1, 3, 5, 6A, 7F and 19A) in the expanded vaccine. IgG anticapsular functional activity was satisfactory for all these serotypes suggesting protection against invasive disease (Second Vaccine Global Congress, Boston, MA, December 7–9, 2008). At Children’s Medical Center Dallas the number of invasive pneumococcal disease (IPD) cases has increased from a low of 36 (41 per 100,000 patients) in 2003 to 58 (68 per 100,000 patients) in 2008 (Chonnamet Techasaensiri, MD). Before routine use of Prevnar® the rate of IPD was 94 cases per 100,000 patients. Although 19A strains still account for many of the recent isolates in Dallas, we are encountering an increasing number of non-typable strains that are currently being characterized. It is unlikely that these latter strains will be prevented from causing IPD by the new 13 valent vaccine when used routinely.
Three cases of invasive disease caused by Neisseria meningitidis, group B were detected in Minnesota and North Dakota from January 2007 through January 2008 (N Engl J Med 2009;360:886). The MIC was 0.25 mcg/mL with resistance defined as 0.12 mcg/mL or greater. All three isolates carried a gyrA mutation associated with flouroquinolone resistance found also in resistant N. gonorrhoeae. One patient, a toddler, had meningococcal meningitis and attended a day care facility in which a worker had died of meningococcal disease approximately 5 months earlier. Other day care workers had received ciprofloxacin prophylaxis whereas the children were given rifampin. It is likely that resistance was acquired by means of horizontal gene transfer from N. lactamica, which is part of the normal flora of the upper respiratory tract. Rifampin or ceftriaxone should be used for meningococcal prophylaxis.
VACCINES IN ADULTS
The immunization status in adults is again emphasized by the American College of Physicians (Ann Intern Med 2009;150:40) and will be the subject of a forthcoming review in the Medical Letter.