Accurate detection of maternal antibodies to HIV in newborn whole blood dried on filter paper.

OBJECTIVE: The testing of neonatal blood specimens dried on filter paper for maternal HIV antibodies, using an enzyme immunoassay (EIA) with confirmation of repeatedly reactive specimens by immunoblot (IB), was first described in 1987. It has been used to conduct large, unlinked, anonymous HIV seroprevalence surveys for surveillance of HIV in child-bearing women in several countries. We directly assessed the sensitivity and specificity of this combination of tests to detect maternal HIV antibodies. SETTING: Serum samples obtained from mothers delivering at a major hospital in Kinshasa, Zaire were screened for HIV antibody using the rapid assay HIVCHEK. DESIGN: Plasma from HIVCHEK-positive women and age-matched negative controls were tested by enzyme-linked immunosorbent assay (ELISA); repeatedly reactive specimens were confirmed by Western blot (WB). Two days after delivery, whole blood was obtained from each newborn by heel-stick, dried on filter paper, and tested by EIA. Repeatedly reactive specimens were confirmed by IB. MAIN OUTCOME MEASURE: The serologic status of neonatal filter-paper specimens was compared with that of corresponding maternal plasma. RESULTS: The testing of neonatal filter-paper specimens using EIA, with confirmatory testing of repeatedly reactive specimens using IB, was 100.0% sensitive [of the 192 ELISA-positive and WB-positive maternal plasma specimens, 192 of the corresponding newborn filter-paper specimens were EIA-positive and IB-positive; 95% confidence interval (CI), 98.1-100]. The detection of maternal HIV antibodies was 99.6% specific using this combination of tests (of the 281 ELISA-negative or ELISA-positive but WB-negative maternal plasma samples, 280 of the corresponding newborn filter-paper specimens were EIA-negative or EIA-positive but IB-negative; 95% CI, 98.0-100). CONCLUSIONS: Maternal HIV antibodies can be detected accurately by testing neonatal blood dried on filter paper, using EIA with confirmation of repeatedly reactive specimens by IB. This approach can facilitate the determination of HIV seroprevalence in child-bearing women in countries with neonatal screening programs, or where serum or plasma is difficult to obtain.

PIP: Neonatal blood specimens dried on filter paper have been tested for maternal HIV antibodies in large, unlinked, anonymous HIV seroprevalence surveys toward the surveillance of HIV in child-bearing women in several countries. This study assesses the sensitivity and specificity of this combination of tests. The standard approach involves first testing the sample via an enzyme immunoassay (EIA), then confirming repeatedly reactive specimens through immunoblot (IB). To test this methodology, serum samples were obtained from mothers delivering at a major hospital in Kinshasa, Zaire, and screened with rapid assay HIVCHEK for antibody to HIV. Plasma from HIVCHEK-positive women and age-matched negative controls were then subjected to ELISA, with repeatedly reactive samples confirmed with Western blot. Whole blood was later obtained by heel-stick from each newborn 2 days after delivery, dried on filter paper, and tested by EIA and IB for confirmation. The serologic statuses of neonatal filter-paper specimens were then compared with those of corresponding maternal plasma. 100% sensitivity was achieved by testing neonatal filter-paper specimens with EIA and confirming with IB. The combination of tests also proved 99.6% specific for detecting maternal HIV antibodies; both results are at 95% confidence intervals. These results demonstrate that maternal HIV antibodies can therefore be detected accurately by testing neonatal blood dried on filter paper, using EIA, then confirming repeatedly reactive specimens via IB. This approach may help determine HIV seroprevalence in childbearing women in countries with neonatal screening programs or where serum or plasma is difficult to obtain.

The role of public health surveillance: information for effective action in public health.

Public health surveillance can provide the quantitative information needed for setting priorities and establishing rational health policy. Although there are many examples of the effective use of such information, the full potential for surveillance has not yet been realized. To a large degree, failure to achieve this potential has resulted from limited perspectives regarding the role and conduct of surveillance. Both practitioners (those who conduct surveillance) and users (those who apply surveillance data in a real-world setting) have fallen victim to such myopia. Public health surveillance must be advocated as an essential part of the global health agenda if we are to achieve international goals for improving health status. As we improve our appreciation of the variety of uses for public health surveillance data, we need to understand more fully the determinants of the decision-making process. Effective dissemination of information and effective communication are as important as data collection and analysis. No longer do we have--or should we have--the luxury of collecting information for its own sake. The information collected must have a demonstrated utility. Developing and training personnel to have expertise in public health surveillance will necessarily incur opportunity costs. Bridging gaps in data methodology and coverage will force us to weigh alternatives and to compromise. We hope that the International Symposium on Public Health Surveillance will accomplish several goals. First, we wish to foster international understanding of the definition, role, and importance of surveillance in reducing morbidity and mortality, in improving quality of life, and in setting effective health priorities. Second, we hope that this symposium will serve as a springboard for identifying issues and topics that can be addressed in greater depth at future international meetings. Finally, we see the symposium as an essential step in developing a firm commitment on the part of countries, donor agencies, and multilateral organizations to develop the essential capacity for public health surveillance throughout the world. Each country should have the capacity to measure and monitor changes in health status, risk factors, and health-service access and utilization among its people. All countries should have the means to detect emerging health problems and implement measures for their control, to evaluate the impact of health policies and programs, and to communicate health information in a meaningful fashion to policymakers and the public. If we are successful in these endeavors, the long-term effects on the public's health will be well worth the struggle required to achieve them.(ABSTRACT TRUNCATED AT 400 WORDS)

An evolving pattern of human hydatid disease transmission in the United States.

Echinococcus granulosus infection was being acquired in the contiguous United States by Virginia sharecroppers and small-holders by the turn of the century. The last recorded human infection from that general area was diagnosed in 1947. By 1920 human infections were also being acquired in the lower Mississippi valley. Apparently, infection in both of these areas was maintained chiefly in swine. By 1940 a third transmission area definitely existed in the Central Valley of California, with its reservoir intermediate host sheep. Seemingly, infection has been disseminated from these California foci into Utah and more recently into northern New Mexico and Arizona. Human populations now at unusual risk in the western United States are transhumant sheep ranchers, including Basque-Americans in California, Mormons in central Utah, and Navajo and Zuni Indians in New Mexico and Arizona. Conditions highly favorable to E. granulosus transmission, intensification and spread now exist throughout relatively large areas of the American West.

Immunization trials with the ring-infected erythrocyte surface antigen of Plasmodium falciparum in owl monkeys (Aotus vociferans).

A protocol was developed for the testing of blood stage vaccines against Plasmodium falciparum using Peruvian Aotus vociferans and the Indochina I/CDC strain of the parasite. Three different fused polypeptide vaccines containing elements of the ring-infected erythrocyte surface antigen molecule combined with Freund's complete and Freund's incomplete adjuvants were tested to determine their ability to protect against overwhelming infection following challenge with this highly virulent strain of P. falciparum, and to invoke antibody responses as measured by a standard indirect immunofluorescence technique. Nine of 14 immunized animals exhibited some protection. Presented are the test procedures developed for the conduct of such trials with New World monkeys and the analysis of results that led to the identification of variables selected for study in future trials.

Infection of chimpanzees with Nigerian I/CDC strain of Plasmodium ovale.

Seven splenectomized chimpanzees were infected with the Nigerian I/CDC strain of Plasmodium ovale. Two of the animals had no history of previous malarial infection whereas three had been infected with P. vivax, one with P. malariae, and one with P. vivax and P. malariae. The two animals with no previous malarial experience had maximum parasitemias of 88,700 and 127,000 per mm3 while the other animals had maximum parasitemias ranging from 10,100 to 60,600 per mm3. Anopheles freeborni, An. dirus, An. stephensi, and An. gambiae were readily infected via membrane feeding on heparinized blood obtained from these chimpanzees during the ascending phases of their primary attacks. The parasitemias in the chimpanzees with previous malarial experience were transient.

Scope and organization of the Guide to Community Preventive Services. The Task Force on Community Preventive Services.

BACKGROUND: The diverse nature of the target audience (i.e., public health decision-makers) for the Guide to Community Preventive Services: Systematic Reviews and Evidence-Based Recommendations (the Guide) dictates that it must be broad in scope. In addition, for the Guide to be most useful for its target audience, its organization and format must be carefully considered. DETERMINING THE SCOPE OF THE GUIDE: Healthy People objectives and actual causes of death were used to determine the contents of the Guide. A priority setting exercise resulted in the selection of 15 topics for systematic reviews using the following criteria: burden of the problem, preventability, relationship to other public health initiatives, usefulness of the package of topics selected and level of current research and intervention activity in public and private sectors. Interventions within each topic target state and local levels and include population-based strategies, individual strategies in other than clinical settings and group strategies. ORGANIZATION OF THE GUIDE: The Guide is organized into: Introduction, Reviews and Recommendations (three sections: Changing Risk Behaviors, Reducing Diseases, Injuries, or Impairments, and Addressing Environmental and Ecosystem Challenges), Appendixes, and Indexes. DISCUSSION: The scope and organization of the Guide were determined using relevant public health criteria and expert opinion to provide a useful and accessible document to a broad target audience. While the final contents of the Guide may change during development, the working table of contents described in this paper provides a framework for development of the Guide and conveys its scope and intention.

Data collection instrument and procedure for systematic reviews in the Guide to Community Preventive Services. Task Force on Community Preventive Services.

INTRODUCTION: A standardized abstraction form and procedure was developed to provide consistency, reduce bias, and improve validity and reliability in the Guide to Community Preventive Services: Systematic Reviews and Evidence-Based Recommendations (the Guide). DATA COLLECTION INSTRUMENT: The content of the abstraction form was based on methodologies used in other systematic reviews; reporting standards established by major health and social science journals; the evaluation, statistical and meta-analytic literature; expert opinion and review; and pilot-testing. The form is used to classify and describe key characteristics of the intervention and evaluation (26 questions) and assess the quality of the study's execution (23 questions). Study procedures and results are collected and specific threats to the validity of the study are assessed across six categories (intervention and study descriptions, sampling, measurement, analysis, interpretation of results and other execution issues). DATA COLLECTION PROCEDURES: Each study is abstracted by two independent reviewers and reconciled by the chapter development team. Reviewers are trained and provided with feedback. DISCUSSION: What to abstract and how to summarize the data are discretionary choices that influence conclusions drawn on the quality of execution of the study and its effectiveness. The form balances flexibility for the evaluation of papers with different study designs and intervention types with the need to ask specific questions to maximize validity and reliability. It provides a structured format that researchers and others can use to review the content and quality of papers, conduct systematic reviews, or develop manuscripts. A systematic approach to developing and evaluating manuscripts will help to promote overall improvement of the scientific literature.

Methods for systematic reviews of economic evaluations for the Guide to Community Preventive Services. Task Force on Community Preventive Services.

OBJECTIVES: This paper describes the methods used in the Guide to Community Preventive Services: Systematic Reviews and Evidence-Based Recommendations (the Guide) for conducting systematic reviews of economic evaluations across community health-promotion and disease-prevention interventions. The lack of standardized methods to improve the comparability of results from economic evaluations has hampered the use of data on costs and financial benefits in evidence-based reviews of effectiveness. The methods and instruments developed for the Guide provide an explicit and systematic approach for abstracting economic evaluation data and increase the usefulness of economic information for policy making in health care and public health. METHODS: The following steps were taken for systematic reviews of economic evaluations: (1) systematic searches were conducted; (2) studies using economic analytic methods, such as cost analysis or cost-effectiveness, cost-benefit or cost-utility analysis, were selected according to explicit inclusion criteria; (3) economic data were abstracted and adjusted using a standardized abstraction form; and (4) adjusted summary measures were listed in summary tables. RESULTS: These methods were used in a review of 10 interventions designed to improve vaccination coverage in children, adolescents and adults. Ten average costs and 14 cost-effectiveness ratios were abstracted or calculated from data reported in 24 studies and expressed in 1997 USD. The types of costs included in the analysis and intervention definitions varied extensively. Gaps in data were found for many interventions.

Developing the Guide to Community Preventive Services--overview and rationale. The Task Force on Community Preventive Services.

When the GUIDE TO COMMUNITY PREVENTIVE SERVICES: Systematic Reviews and Evidence-Based Recommendations (the Guide) is published in 2001, it will represent a significant national effort in encouraging evidence-based public health practice in defined populations (e.g., communities or members of specific managed care plans). The Guide will make recommendations regarding public health interventions to reduce illness, disability, premature death, and environmental hazards that impair community health and quality of life. The Guide is being developed under the guidance of the Task Force on Community Preventive Services (the Task Force)-a 15-member, nonfederal, independent panel of experts. Subject matter experts, methodologists, and scientific staff are supporting the Task Force in using explicit rules to conduct systematic literature reviews of evidence of effectiveness, economic efficiency, and feasibility on which to base recommendations for community action. Contributors to the Guide are building on the experience of others to confront methodologic challenges unique to the assessment of complex multicomponent intervention studies with nonexperimental or nonrandomized designs and diverse measures of outcome and effectiveness. Persons who plan, fund, and implement population-based services and policies to improve health at the state and local levels are invited to scrutinize the work in progress and to communicate with contributors. When the Guide is complete, readers are encouraged to consider critically the value and relevance of its contents, the implementation of interventions the Task Force recommends, the abandonment of interventions the Task Force does not recommend, and the need for rigorous evaluation of the benefits and harms of promising interventions of unknown effectiveness.

Developing an evidence-based Guide to Community Preventive Services--methods. The Task Force on Community Preventive Services.

Systematic reviews and evidence-based recommendations are increasingly important for decision making in health and medicine. Over the past 20 years, information on the science of synthesizing research results has exploded. However, some approaches to systematic reviews of the effectiveness of clinical preventive services and medical care may be less appropriate for evaluating population-based interventions. Furthermore, methods for linking evidence to recommendations are less well developed than methods for synthesizing evidence. The Guide to Community Preventive Services: Systematic Reviews and Evidence-Based Recommendations (the Guide) will evaluate and make recommendations on population-based and public health interventions. This paper provides an overview of the Guide's process to systematically review evidence and translate that evidence into recommendations. The Guide reviews evidence on effectiveness, the applicability of effectiveness data, (i.e., the extent to which available effectiveness data is thought to apply to additional populations and settings), the intervention's other effects (i.e., important side effects), economic impact, and barriers to implementation of interventions. The steps for obtaining and evaluating evidence into recommendations involve: (1) forming multidisciplinary chapter development teams, (2) developing a conceptual approach to organizing, grouping, selecting and evaluating the interventions in each chapter; (3) selecting interventions to be evaluated; (4) searching for and retrieving evidence; (5) assessing the quality of and summarizing the body of evidence of effectiveness; (6) translating the body of evidence of effectiveness into recommendations; (7) considering information on evidence other than effectiveness; and (8) identifying and summarizing research gaps. Systematic reviews of and evidence-based recommendations for population-health interventions are challenging and methods will continue to evolve. However, using an evidence-based approach to identify and recommend effective interventions directed at specific public health goals may reduce errors in how information is collected and interpreted, identify important gaps in current knowledge thus guiding further research, and enhance the Guide users' ability to assess whether recommendations are valid and prudent from their own perspectives. Over time, all of these advantages could help to increase agreement regarding appropriate community health strategies and help to increase their implementation.

Monitoring the levels and trends of HIV infection: the Public Health Service's HIV surveillance program.

A comprehensive, multifaceted approach to HIV surveillance is needed to provide the information necessary for public health management and policy. Because HIV infection is not readily or uniformly ascertained, survey methods and sentinel surveillance approaches must be used. At least some of the surveys must be blinded, that is, anonymous and unlinked to identifiable persons, to avoid the uninterpretable impact of self-selection bias that could lead to both significant underestimates and occasional overestimates of HIV prevalence. Other surveys must be nonblinded, with careful interviews of volunteer participants to evaluate risk factors for HIV infection. These various surveys must continue over time to evaluate trends in infection. A comprehensive family of complementary HIV surveys and studies and a national household-based HIV seroprevalence survey have been undertaken by the Public Health Service in collaboration with other Federal agencies, State and local health departments, blood collection agencies, and medical research institutions. These projects focus on accessible segments of the general population, childbearing women, persons at high risk for HIV, and persons in special settings such as prisons and colleges. This comprehensive surveillance approach will help monitor the levels and trends of HIV infection in the United States and help prioritize, target, and evaluate HIV prevention activities.

HIV seroprevalence surveys in sexually transmitted disease clinics.

The Centers for Disease Control, in cooperation with State and local health departments, is conducting human immunodeficiency virus, type 1 (HIV), seroprevalence surveys, using standard protocols, in sexually transmitted disease (STD) clinics in selected metropolitan areas throughout the United States. The surveys are blinded (serologic test results not identified with a person) as well as nonblinded (clients voluntarily agreeing to participate). STD clinics are important sentinel sites for the surveillance of HIV infection because they serve persons who are at increased risk as a result of certain behaviors, such as unprotected sex, homosexual exposure, or intravenous drug use. HIV seroprevalence rates will be obtained in the sentinel clinics each year so that trends in infection can be assessed over an extended period of time. Behaviors that place clients at risk for infection, or protect against infection, are being evaluated in voluntary, nonblinded surveys to define groups for appropriate interventions and to detect changes in response to education and prevention programs. Although inferences drawn from the surveys are limited by the scope of the clinics and clients surveyed, HIV trends in STD clinic client populations should provide a sensitive monitor of the course of the acquired immunodeficiency syndrome (AIDS) epidemic among persons engaging in high-risk sexual behaviors.

HIV seroprevalence surveys in drug treatment centers.

Sharing of equipment used to inject illicit drugs intravenously is a risk factor for human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS). Systematic surveillance of HIV infection among intravenous drug users (IVDUs) in the United States is essential to monitor the HIV epidemic and to target and evaluate prevention programs for IVDUs and their partners. The most accessible segment of the largely covert population of IVDUs are those in drug treatment programs. In collaboration with State and local health departments and drug abuse treatment agencies, the Centers for Disease Control is conducting blinded (serologic test results not linked to identifiable persons) and nonblinded (in which clients voluntarily agree to participate) surveys of IVDUs entering drug treatment in 39 U.S. metropolitan areas. The same protocol is used in all participating drug treatment centers. Blinded surveys will be carried out annually to determine HIV seroprevalence rates in eligible IVDUs entering drug treatment and to monitor trends over time. Each year, nonblinded surveys of IVDUs entering drug treatment will assess self-reported drug use and sexual behaviors to help design educational interventions and to detect changes in behavior over time. This sentinel surveillance system, using a standardized methodology, will provide the best national and regional data available on the seroprevalence of HIV among IVDUs and the relationships of drug use, sexual behaviors, and HIV serologic status of IVDUs.

Determining HIV seroprevalence among women in women's health clinics.

Human immunodeficiency virus, type 1 (HIV), seroprevalence studies are needed to determine the level and trends of HIV infection among women attending family planning, abortion, and prenatal care clinics in the United States. A review of published and unpublished studies showed that HIV seroprevalence among women attending women's health clinics was 0 to 2.6 percent, although the studies were difficult to compare because of differences in methodology. The Centers for Disease Control, in association with State and local health departments, has developed a standardized protocol to determine HIV seroprevalence among women attending women's health clinics in selected metropolitan areas. Blinded HIV serosurveys (serologic test results not identified with a person) are being conducted annually in selected sentinel clinics in order to obtain estimates of HIV seroprevalence unbiased by self-selection, as well as to monitor trends in infection among clients attending these clinics. In areas with high HIV seroprevalence, nonblinded serosurveys (in which clients voluntarily agree to participate) will be used to assess behaviors that may place women at increased risk of exposure to HIV. Data from the surveys can be used in developing age-specific and culturally appropriate AIDS educational materials, assessing the amount and type of counseling activities required, and evaluating acquired immunodeficiency syndrome (AIDS) prevention activities. The information will provide epidemiologic data to complement the results of other surveys in characterizing the scope of HIV infection among women of childbearing age in the United States.

The family of HIV seroprevalence surveys: objectives, methods, and uses of sentinel surveillance for HIV in the United States.

During 1987-89, the Centers for Disease Control (CDC), in collaboration with State and local health departments, other Federal agencies, blood collection agencies, and medical research institutions, implemented a national sentinel surveillance system for human immunodeficiency virus (HIV) infection. This ongoing surveillance system, known as the CDC family of HIV seroprevalence surveys, uses standardized survey and HIV serologic testing procedures in a group of sentinel populations from geographically diverse metropolitan areas, States, and Territories of the United States. As of September 1989, sentinel surveillance for HIV infection was being conducted in 41 States, Puerto Rico, and 39 metropolitan areas, including the District of Columbia. Information from this system complements AIDS surveillance data to assist health officials to direct resources and develop strategies for HIV prevention and health-care programs.

HIV seroprevalence surveys of childbearing women--objectives, methods, and uses of the data.

A seroprevalence survey of human immunodeficiency virus (HIV) among childbearing women is being conducted in 43 States and Territories as one of the family of HIV seroprevalence surveys. This blinded survey, in which serologic test results are not linked to identifiable persons, uses neonatal dried blood specimens on filter paper to test for maternal antibodies to HIV. This survey provides relatively unbiased estimates of prevalence of HIV infection in the population of women delivering live children during given survey periods, by month or quarter of delivery, geographic area, and demographic subgroup. This objective will be met while protecting the integrity and efficient conduct of neonatal screening programs and ensuring patient anonymity. Information from this survey will be used to (a) assess the levels and trends of HIV infection in women and infants, (b) help develop and evaluate prevention programs, and (c) project the number of women and children who will develop HIV infection and the acquired immunodeficiency syndrome (AIDS) and will require health care and social services in the future.

The sporogonic cycle of Plasmodium reichenowi.

Plasmodium reichenowi, a malarial parasite of the chimpanzee, was infective to Anopheles freeborni, Anopheles quadrimaculatus, Anopheles stephensi, Anopheles maculatus, Anopheles dirus, and Anopheles culicifacies mosquitoes. Anopheles gambiae and Anopheles albimanus were not infected. Mean oocyst diameters of P. reichenowi were smaller than those of the other chimpanzee parasite, Plasmodium schwetzi. Sporozoites were present in the salivary glands of An. freeborni at 15 days when held at 25 to 26 C.

Infection of Aotus vociferans (karyotype V) monkeys with different strains of Plasmodium vivax.

Twenty splenectomized Aotus vociferans (karyotype V) monkeys were infected with strains of Plasmodium vivax from New Guinea, North Korea, Indonesia, El Salvador, and Honduras. Peak parasite densities ranged from 4,840 to 75,500 per mm3. Gametocytes infective to different species of mosquitoes were produced with all strains of P. vivax studied. Two transmissions of the Chesson strain of P. vivax were made by the intravenous inoculation of dissected sporozoites from An. dirus mosquitoes. Prepatent periods were 16 days.

Infection of Peruvian Aotus nancymai monkeys with different strains of Plasmodium falciparum, P. vivax, and P. malariae.

Aotus nancymai (karyotype I) monkeys from Peru were studied for their susceptibility to infection with Plasmodium falciparum, P. vivax, and P. malariae. Three strains of P. falciparum (Santa Lucia from El Salvador, Indochina I/CDC from Thailand, and Uganda Palo Alto) were inoculated into 38 monkeys. The results indicated that this species of Aotus monkey is highly susceptible to infection. The Uganda Palo Alto and the Santa Lucia strain parasites appear to be the most useful for immunologic and chemotherapeutic studies. Five strains of P. vivax (Chesson, ONG, Vietnam Palo Alto, Salvador I, and Honduran I/CDC) were inoculated into 28 monkeys. The Vietnam Palo Alto strain produced the highest level parasitemias ranging from 23,800 to 157,000/mm3. Mosquito infections were obtained with the ONG, Chesson, and Salvador I strains. Two out of 6 attempts to transmit P. vivax via sporozoite inoculation to splenectomized monkeys were successful with prepatent periods of 39 and 57 days. Five monkeys were infected with the Uganda I/CDC strain of P. malariae. Maximum parasitemias ranged from 10 to 5,390/mm3.

The Uganda I/CDC strain of Plasmodium malariae in Aotus lemurinus griseimembra monkeys.

Two lines of the Uganda I/CDC strain of Plasmodium malariae were studied in splenectomized Aotus lemurinus griseimembra monkeys. A line initially adapted to these monkeys from an infected chimpanzee failed to produce high-level parasite counts or mosquito infection in 13 of this type of monkey during 16 linear passages. Another line, originally adapted from the chimpanzee to Aotus azarae boliviensis, after 7 linear passages in 3 different types of Aotus was then passaged to 14 splenectomized A. lemurinus griseimembra. Geometric mean maximum parasitemia in these monkeys was 18,400/mm3. Mosquito infections were readily obtained during the period just after the parasite count rose above 1,000/mm3. Anopheles freeborni, An. stephensi, An. dirus, and 2 strains of An. gambiae supported the development of the parasite to the presence of sporozoites in the salivary glands. Two attempts to transmit the strain to other splenectomized A. lemurinus griseimembra by sporozoite inoculation were unsuccessful.