PM2ch34.pdf

Laboratory Support for Infectious Disease Investigations in the Field

Chapter 34

LABORATORY SUPPORT FOR

INFECTIOUS DISEASE INVESTIGATIONS

IN THE FIELD

EDWARD T. CLAYSON, P H D AND CARL J. MASON, MD, MPH

INTRODUCTION

STUDY CONSIDERATIONS

LABORATORY DIAGNOSIS OF INFECTION

Identification of Microorganisms by Microscopic Examination

Identification of Microorganisms by Isolation and Culture

Detection of Microbial Components or Products

Detection of Antibodies to Microorganisms

Diagnostic and Reporting Issues

SPECIMEN COLLECTION, HANDLING, AND STORAGE

Practical Issues

Specimens for Microscopic Examination

Specimens for Culture

Specimens for Detection of Microbial Components or Products

Specimens for Detection of Antibodies

SPECIMEN SHIPPING

Timely Delivery

Regulatory Issues

Containers

Volume Limitations

Temperature

Labeling

Inventory and Clinical Information

SUMMARY

783

Military Preventive Medicine: Mobilization and Deployment, Volume 2

E.T. CLAYSON ; Lieutenant Colonel, MS, US Army; Product Manager, Joint Vaccine Acquisition Program, 64 Thomas Jefferson Dr.,

Frederick, MD 21702

C.J. MASON ; Colonel, Medical Corps, US Army; Commander, USAMC-AFRIMS, APO AP 96546-5000

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Laboratory Support for Infectious Disease Investigations in the Field

INTRODUCTION

Infectious disease surveillance and outbreak in-

vestigations in a field environment differ significantly

from those conducted in a hospital, clinic, or labora-

tory and require special planning and coordination.

Microbiology laboratory support may be hundreds

or even thousands of miles away from a theater of

military operations. Methods of specimen collec-

tion, storage, and transportation routinely used in

a clinical setting are often not appropriate in a field

setting. This chapter describes some of the special

laboratory considerations needed to conduct infec-

tious disease surveillance and outbreak investiga-

tions in a field environment. It was written for the

military specimen collector and is not meant to be

a laboratory guide for microbiologists. Consider-

ations are discussed below for planning investiga-

tions, such as study purpose, study design, and

laboratory support. Brief descriptions of common

microbiological diagnostic methods are provided

to aid in the selection of proper specimens for ex-

amination. Special considerations for specimen col-

lection, handling, and storage are described. And

finally, issues relating to specimen shipping are

discussed. This information provides the medical

investigator with the knowledge necessary to en-

sure that an investigation yields results that are

useful to both the health care provider and the mili-

tary commander.

STUDY CONSIDERATIONS

The usefulness of the information to be gained from

a field study depends greatly on careful planning and

coordination before the study begins. Issues such as

study purpose and design must be addressed before

the start of the study (see Chapter 32, Outbreak In-

vestigation). Laboratory support is also an issue that

needs to be addressed early. Preventive medicine per-

sonnel need to understand the available laboratory

resources; this will aid in coordination and facilitate

testing and reporting. Deployable military medical fa-

cilities are not usually equipped with microbiology

laboratory capabilities, so organic microbiology labo-

ratory capabilities are often lacking in the theater.

However, during some large-scale operations, the

Theater Area Medical Laboratory or the Navy For-

ward Laboratory may be deployed to provide some

diagnostic capabilities to the theater of operations. 1

These laboratories are staffed with selected person-

nel and equipped with relevant but limited diagnos-

tic capabilities. Often permanent (nondeployable)

laboratories must be solicited for support. Army and

Navy infectious disease research laboratories can

serve as both reference and support centers (Exhibit

34-1). Because these laboratories have been given a

formal mission of surveillance for emerging infectious

diseases and provided with a budget to conduct sur-

veillance and outbreak investigations, they can be

considered for laboratory support for an infectious

disease outbreak or surveillance investigation. If

support from the military medical system is not

available for the disease of interest, support from an

international reference laboratory may be obtained.

A partial list of international laboratories is shown in

Exhibit 34-2.

LABORATORY DIAGNOSIS OF INFECTION

A principal role of a clinical microbiology labo-

ratory is to provide accurate information about the

presence or absence of microorganisms that may be

involved in a patient’s disease process. In a military

environment, the identification of causative organ-

isms is important for two reasons: first, therapeu-

tic intervention is now possible for many infectious

diseases, thus allowing for earlier return to duty of

infected personnel, and second, combat commanders

need to be informed of the medical threats facing

their units.

A fundamental step in any diagnosis is the choice

of an appropriate specimen, which ultimately de-

pends on an understanding of the pathogenesis of

infectious diseases. Awareness of the types of diag-

nostic tests available and their complexity will facili-

tate choosing the appropriate specimen (Table 34-1).

Microbiological tests fall into four main categories: (1)

identification of microorganisms by microscopic ex-

amination, (2) identification of microorganisms by

isolation and culture, (3) detection of a specific mi-

crobial component or product, and (4) detection of

specific antibodies to a microorganism. 2 General

principles and applicability of various diagnostic

assays in each of these four categories will be dis-

cussed below and are shown in Table 34-2. The in-

formation provided is not meant to be a “cookbook”

description of each assay for use by a microbiologist.

Rather, information is provided to aid medical inves-

tigators in the field in identifying and collecting

appropriate specimens for transport to supporting

laboratories.

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Military Preventive Medicine: Mobilization and Deployment, Volume 2

EXHIBIT 34-1

LIST OF US DEPARTMENT OF DEFENSE MEDIAL RESEARCH LABORATORIES

FOR INFECTIOUS DISEASES *

Army CONUS Laboratories

Walter Reed Army Institute of Research

503 Robert Grant Avenue

Silver Spring, MD 20910-7500

Phone: (301) 319-9100

Fax:

(301) 319-9227

Navy CONUS Laboratory

Naval Medical Research Command

503 Robert Grant Ave

Silver Spring, MD 20910-7500

Phone: (301) 319-9208

Fax:

(301) 319-7410

US Army Medical Research Institute of Infectious

Diseases

1425 Porter Street

Fort Detrick, MD 21702-5011

Phone: (301) 619-2833

Fax:

(301) 619-4625

Navy OCONUS Laboratories

Naval Medical Research Institute Detachment

(Peru)

American Embassy, Unit 3800

APO AA 34031

Phone: 51-1-561-2733

Fax:

Army OCONUS Laboratories

Armed Forces Research Institute of Medical

Sciences

US Army Medical Component—Thailand

APO AP 96546

Phone: 66-2-644-4888

Fax:

51-1-561-3042

US Naval Medical Research Unit No. 2 (Indonesia)

Box 3, Unit 8132

APO AP 96520-8132

Phone: 62-21-421-4457

Fax:

62-21-424-4507

66-2-247-6030

US Naval Medical Research Unit No. 3 (Egypt)

PSC 452, Box 5000

FPO AE 09835-0007

Phone: 20-2-684-1375

Fax:

US Army Medical Research Unit—Kenya

Unit 64109 Box 401

APO AE 09831-4109

Phone: 254-2-729-303

Fax:

20-2-684-7139

254-2-714-592

* Telephone and fax numbers may have changed.

CONUS: continental United States

OCONUS: outside the continental United States

Identification of Microorganisms by Microscopic

Examination

in the support laboratory. A description of the prin-

ciples and applicability of the various microscopy

methods is beyond the scope of this chapter but can

be found in common microbiological laboratory

texts. 3–5

Direct microscopic inspection of clinical specimens

is usually the fastest and most economical method

available for the detection of microorganisms. Some

infectious agents can be reliably identified with only

a few simple stains and a basic microscope—with-

out the need for time-consuming and expensive

cultivation techniques. In addition, microscopic

methods sometimes permit diagnosis of infections

when microorganisms cannot be cultivated and in

specimens where the microorganism is no longer

viable. Numerous methods for microscopic exami-

nation exist, including bright field, dark field,

phase-contrast, fluorescence, and electron micros-

copy. The best method to use in a given situation

depends on the equipment and reagents available

Identification of Microorganisms by Isolation

and Culture

In general, rapid diagnostic methods, which today

exist for a broad range of microorganisms, are pre-

ferred over the time-consuming and labor-intensive

methods of isolation and cultivation. Cultivation of

microorganisms requires a day to several weeks, but

many of today’s rapid diagnostic methods require

only a few minutes to a few hours. Nevertheless,

cultivation is still the gold standard for diagnosis

of infectious diseases, and it is likely to remain one

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Laboratory Support for Infectious Disease Investigations in the Field

EXHIBIT 34-2

PARTIAL LIST OF INTERNATIONAL REFERENCE LABORATORIES

FOR COMMUNICABLE DISEASES *

Center for Applied Microbiology Research

Porton Down

Salisbury Wiltshire SP4 0JG

United Kingdom

Phone: 44-1980-612100

Fax: 44-1980-611096

www.camr.org.uk

National Institute of Infectious Disease, Japan

1-23-1 Toyama

Tokyo 162-8640

Japan

Phone: 81-3-5285-1111

Fax: 81-3-5282-1150

www.nih.go.jp

Centers for Disease Control and Prevention

National Center for Infectious Diseases

1600 Clifton Road, N.E.

Atlanta, Georgia 30333

USA

Phone: 1-800-311-3435

Fax: 1-404-639-2334

www.cdc.gov

Public Health Laboratory Service

61 Colindale Ave

Colindale, London NW9 5HT

United Kingdom

Phone: 44-181-2004400

Fax: 44-181-2007874

www.phls.co.uk

South African Medical Research Council

PO Box 9070

7505 Tygerberg

Republic of South Africa

Phone: 27-21-9380911

Fax: 27-21-9380200

www.mrc.ac.za

Epicentre

8 Rue St Sabin

75011 Paris

France

Phone: 33-1-40-212850

Fax: 33-1-40-212803

Statens Seruminstitut

Artillerivej 5

2300 Kobenhavn S

Denmark

Phone: 45-32-683268

Fax: 45-32-683868

www.serum.dk

* Specimens should be forwarded to these or other laboratories only after consultation. Proper shipping

containers must be used, and all regulations for shipping hazardous, high-risk specimens must be ob-

served. Telephone and fax numbers may have changed.

of the more important microbiological methods in

the laboratory for some time. Cultivation of micro-

organisms isolated from patient specimens is often

necessary before laboratory technicians can carry out

the multitude of assays needed to identify or differ-

entiate the agent from among various disease-caus-

ing agents or determine the susceptibility of isolated

microorganisms to various antimicrobial agents.

Unfortunately, there is no universal method for

the cultivation of all microorganisms. Each micro-

organism has its own optimum conditions for

growth, which vary widely. The determination of

the optimum cultivation conditions for various mi-

croorganisms has taken years of experimentation,

and the optimum conditions for many microorgan-

isms remain unknown. However, the various meth-

ods available for the cultivation of a broad range of

microorganisms can be divided into three main

categories: cultivation using artificial media, cultiva-

tion using cell culture, and cultivation using experi-

mental animals. Descriptions of these methods can be

found in common microbiological laboratory texts. 2,6

Detection of Microbial Components or Products

Clinical microbiologists now have many new tech-

niques to aid them in the laboratory diagnosis of in-

fectious diseases. These new methods may involve the

detection of structural components of the microorgan-

ism, detection of microbial products (eg, toxins), or

787

Institut de Medicine Tropicale Prince Leopold

Nationalestraat 155

B-2000 Antwerp

Belgium

Phone: 32-3-247-6666

Fax: 32-3-216-1431

www.itg.be

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