Experimental milk-borne transmission of Powassan virus in the goat.

A lactating goat with a 74-day-old kid was inoculated with 10(3) mouse 50% lethal dose (LD50) of Powassan virus. No ensuing viremia could be detected, but virus was secreted in the milk on postinoculation days 7 through 15, with a titer of 10(5) LD50/ml on day 12. Neutralizing antibody was found in the serum on days 22 through 36 and in the milk on day 36. The offspring was not inoculated but was allowed to continue feeding on its mother's milk. It developed neutralizing antibody by day 22. Since the kid was past the age when it could resorb antibody from the milk, its serum antibody was evidence of active infection. Neither animal showed any clinical sign of illness. A serum survey of 499 goats in New York State showed that 9 had neutralizing antibodies to Powassan virus. These immune goats came from widely scattered localities, including counties where human cases have been confirmed. The findings suggest the possibility of milk-borne transmission of Powassan virus from goat to man.

Arboviruses in New York State: an attempt to determine the role of arboviruses in patients with viral encephalitis and meningitis.

In a reveiw of 2,963 patients with signs of infections of the central nervous system in New York State in 1966--1977, arboviruses were found to be the confirmed or presumptive etiologic agents in 60 patients. California encephalitis (CE) virus was the most common (44 patients), followed by Powassan (POW) virus (8), St. Louis encephalitis virus (7), and eastern equine encephalitis (EEE) virus (1). Most patients (47) were children. The incidence of encephalitis was higher in patients with arbovirus findings than in infections with any other of the common neurotropic viruses. The disease was fatal in two patients, one infected with POW virus, the other with EEE virus. Most patients with CE virus infections resided in suburban areas. All POW infections were contracted in six rural counties known for their recreational facilities.

Dengue shock syndrome in an American traveler with primary dengue 3 infection.

A previously reported case of childhood dengue shock syndrome in an American traveler to India was investigated serologically. The original studies neither indicated the infecting serotype nor proved primary or secondary infection. However, BHK suspension PRNT of 6-year convalescent serum now indicates that the child had primary dengue type 3 infection. Dengue, dengue hemorrhagic fever, and dengue shock syndrome are potential hazards for American travelers and American residents of dengue-receptive areas.

Pacui virus, phlebotomine flies, and small mammals in Brazil: an epidemiological study.

Pacui virus, originally obtained from forest rodents, was isolated 100 times from 61,437 specimens (658 pools) of the phlebotomine fly Lutzomyia flaviscutellata, collected from rodent-baited traps in the forests of Belem, Para, Brazil in the period October 1968 through September 1970. Isolations were made from engorged and unengorged females and from males (3 strains), and occurred in all 24 months. Pacui virus also was isolated from the blood of two wild rodents (Oryzomys), but not from 424 L. infraspinosa, 12,000 mosquitoes, or sentinel mice. Pacui virus neutralizing antibodies were detected in serum of six bait animals after exposure to biting flies in the forest, in 30% of wild rodents surveyed (including two from Amapa Territory), and in 10% of marsupials, but were absent in human survey sera and in bats. Low-passage Pacui virus produced viremia in and was lethal to infant mice by the subcutaneous route. L. flaviscutellata was most abundant in the dry season, in which period Pacui virus isolations increased. This fly is strongly attracted to rodents close to the ground. L. flaviscutellata also yielded single strains of Guama, Icoaraci, and BeAr 177325 viruses.

Epidemic dengue fever in Puerto Rico, 1977: a cost analysis.

During the period July-December 1977, a widespread epidemic of dengue fever occurred in Puerto Rico. The cost of the epidemic was calculated, using upper and lower limit incidence figures, in terms of direct costs (medical care and epidemic control measures) and indirect costs (lost production of ill workers and parents of ill children). Direct costs were estimated to range between $2.4 and $4.7 million. Indirect costs were calculated by using current (1977) employment and wage data and population extrapolations from the 1970 census, and entailed a loss to the Puerto Rico economy of from $3.7 to $10.9 million. The total cost of this epidemic, therefore, was estimated to be in a range of $6.0 to $15.6 million, of which epidemic control measures comprised 7.8--20.2%.

Dengue in Puerto Rico, 1977: public health response to characterize and control an epidemic of multiple serotypes.

The largest and most extensive documented dengue epidemic in Puerto Rico struck an estimated 355,000 Puerto Rican residents from July-December 1977. The mixed epidemic of dengue types 2 and 3 coincided with a Caribbean pandemic of dengue type 1, first introduced into the western hemisphere in early 1977 and into Puerto Rico in the fall of that year. Health officials assembled a team to assess the epidemic and mounted a campaign to end it. Attempts to monitor the incidence and spread of dengue were confounded by simultaneous co-circulation of influenza virus, underscoring problems in formulating public health strategies dependent on nonspecific clinical and epidemiologic case criteria, and the need for rapid and reliable diagnostic capabilities. Despite co-circulation of multiple dengue serotypes, a risk factor associated with severe and fatal dengue hemorrhagic fever (DHF) in Southeast Asia, hospital and death certificate surveillance disclosed no cases of DHF in Puerto Rico. The epidemic serves as a reminder that when preventive measures are impossible or infeasible, developed countries with high living standards may be susceptible to large scale epidemics of infectious diseases.

Preparation for emergency relief after biological warfare.

Upon invitation by the World Health Organization during the Gulf War, a task force "Scorpio" independent from the nations involved in the armed conflict was formed whose task was to determine whether, which and to what extent biological warfare agents had been used. risk assessment concluded that anthrax and Clostridium botulinum toxin were the major risks. The 21 civilian experts had rapidly to decide on the doctrine of operation, to assemble material which could be used and to be immunized or protected otherwise against the potential risks. Biological warfare agents may be used anywhere any time, be it by terrorists or during open or clandestine hostilities. The general population cannot rely on the military to take care of civilian relief, thus international and national organizations may wish to establish similar task forces basing on the "Scorpio" model on a national or regional basis.

Lymphocytic choriomeningitis in laboratory personnel exposed to hamsters inadvertently infected with LCM virus.

Seven of 27 students and staff oa a university laboratory became ill with lymphocytic choriomeningitis (LCM) following exposure over an 18-month period to hamsters implanted with tumors. The clinical symptoms were compatible with LCM infection and all the patients' sera had fluorescent antibody to LCM virus; 5 of them also had complement-fixing (CF) antibodies. Complement-fixing antibodies were found in 9 of 9 hamsters with tumors and 16 of 31 without tumors (excluding 6 hamsters with anticomplementary sera) and in 8 of 14 rabbits, but in none of 49 rats. Lymphocytic choriomeningitis virus was isolated from 4 pools of liver and spleen, 2 each from hamsters with and without tumors, and from a frozen stored sample of the tumor cells. Interlaboratory transmission may have occurred via infected tumor cells. Control was achieved by destroying all animals in the project room as well as all hamsters in the building. The possibility that many tumor cell lines carried in hamsters may be infected with LCM virus has important implications for laboratory safety as well as for the validity of the research results obtained, inasmuch as the virus enhances the growth of some tumors and retards others.

Global surveillance of emerging diseases: the ProMED-mail perspective.

The Internet is changing the way global disease surveillance is conducted. Countries and international organizations are increasingly placing their outbreak reports on the Internet, which speeds up distribution and therefore prevention and control. The World Health Organization (WHO) has recognized the value of nongovernmental organizations and the media in reporting outbreaks, which it then attempts to verify through its country offices. However, WHO and other official sources are constrained in their reporting by the need for bureaucratic clearance. ProMED-mail has no such constraints, and posts outbreak reports 7 days a week. It is moderated by infectious disease specialists who add relevant comments. Thus, ProMED-mail complements official sources and provides early warning of outbreaks. Its network is more than 20,000 people in over 150 countries, who place their computers and time at the network's disposal and report on outbreaks of which they have knowledge. Regions and countries could benefit from adopting the ProMED-mail approach to complement their own disease surveillance systems.

Epidemiological approaches to health planning, management and evaluation.

The promotion of health and the prevention of disease depend to a large extent on the good planning and management of health programmes. Good planning and management in turn depend on the availability of reliable, accurate and timely information about the health situation. All countries have institution-based systems for the collection of routine information about health-services delivery. Many countries also use surveys to obtain information about other aspects of the health situation. This issue of the World health statistics quarterly describes two types of surveillance which may be used to supplement (or compensate for the absence of) nationwide routine systems or surveys, and a method for evaluating surveillance systems. It also includes articles on the International Classification of Diseases and Causes of Death (ICD) and the International Health Regulations (IHR) in relation to their use for planning and management. Two alternative surveillance systems are described. One uses institution- or city-based records of incidence of target diseases of the Expanded Programme on Immunization (EPI) in a number of developing countries to determine the impact of minimization on the reduction of disease. In this article, some additional background material is reviewed on sentinel hospitals and cities in India, Bangladesh, Turkey, Malawi and United Republic of Tanzania. The other system is based on district-level household surveys of mortality, morbidity and nutrition-related indicators in Kerala State (India) carried out by trained local personnel who live in the districts.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of immunization policies for peacekeeping missions.

This article first examines data bases available to assess the risk of vaccine-preventable diseases (VPD). In the second part, immunization recommendations and practices are briefly evaluated in view of the risk of exposure to VPD and of the efficacy and safety of available vaccines.

Lymphocytic choriomeningitis virus in man. Serologic evidence of association with pet hamsters;.

Laboratory evidence of recent or current lymphocytic choriomeningitis (LCM) virus infection was obtained in 60 patients. Twelve had diagnosis of central nervous system (CNS) infection: four of meningoencephalitis and eight of meningitis. Thirty-four patients had a grippe-like syndrome. Fifty-nine had had contact with pet hamsters. All of the 24 patients whose pets were studied had been exposed to one or more hamsters with serologic evidence of past LCM virus infection. The data implicate pet hamsters as a source of LCM in man. A continuous effective control of LCM virus in pet hamsters appears impractical. At present, the only feasible way to prevent further cases is the physician's special attention to the possibility of rodent contacts of patients with CNS disease and early laboratory confirmation of suspected cases of human LCM virus infections.

Lymphocytic choriomeningitis outbreak associated with pet hamsters. Fifty-seven cases from New York State;.

An outbreak of lymphocytic choriomeningitis (LCM) associated with pet hamsters adquired through nationwide distributor was recognized in New York in February 1974. In upstate a New York, 57 cases occurred in a four-month period. Complete information was obtained on 49 patients ranging in age from 3 to 70 years. Characteristic findings included fever (90%), headache (85%), and severe myalgia (80%). Typically, laboratory findings consisted of a normal blood cell count and cerebrospinal fluid with mononuclear leukocyte pleocytosis and moderate hypoglycorrhacia. Al patients had contact with hamsters from one distributor. Most of the hamsters were acquired in mid to late December 1973, but some as late as March 1974. From each of eight families in which hamsters were available, at least one hamster had detectable complement-fixing antibodies for LCM. Infection rates within families varied with location and type of hamster cage; open cages and cages situated in common living areas were associated with highest infection rates (45% and 52%, respectively). Severity of illness was not associated with direct contact with hamsters. Onset of illness occurred between 8 and 90 days after initial exposure to hamsters.

Lack of greater seroconversion of rhesus monkeys after subcutaneous inoculation of dengue type 2 live-virus vaccine combined with infection-enhancing antibodies.

Four groups of six nonimmune male rhesus monkeys were inoculated subcutaneously with formulations of dengue type 2 vaccine virus DEN-2/S-1. Group A received 1.9 x 10(4) plaque-forming units of vaccine in normal human serum albumin diluent. Group B received the same dose combined with a dengue type 2-immune human serum diluted 1:1,600, beyond its neutralization endpoint of 1:300, but having an immune enhancement titer of 250,000. Groups C and D received 10-fold dilutions of these respective formulations. No migration-inhibitory factor was found when peripheral blood mononuclear leukocytes obtained on day 68 post-immunization from monkeys of all experimental groups were tested. No viremia was detected in any of the monkeys when sera taken on postvaccination days 1 through 12 were inoculated into adult Toxorhynchites amboinensis mosquitoes and LLC-MK2 cells. By day 89, four of the six monkeys had seroconverted by the neutralization test in each of groups A, B, and C, and three of five monkeys in group D (one monkey died from cardiac collapse after anesthesia) had seroconverted. Immune enhancement of dengue virus infection is known to occur in humans and monkeys circulating heterologous flavivirus antibodies. In this study, there was no enhancing effect when antibody was mixed with dengue type 2 vaccine virus and injected subcutaneously.