LN Technical Standards, Durability and

New products

Dr Rajpal Yadav

WHOPES

Dept. of Control of Neglected Tropical Diseases

Dr Abraham Mnzava Vector Control Unit

Global Malaria Programme

WHO definition of an LN

• An LN is a factory-treated mosquito net that is

expected to retain its biological activity for:

– a minimum number of standard washes under

laboratory conditions ( = 20)

– a minimum period of use under field

conditions (= 3 years)

– LLIN or LN?

Criteria for efficacy of an LN

• After 20 washes, the netting must

produce, in:

• Efficacy criteria cannot be used for quality

control

• Hence the use of physico-chemical criteria

Cone bioassays ≥ 80% mortality and/or ≥ 95% knockdown

Tunnel test ≥ 80% mortality and/or ≥ 90% blood-feeding inhibition

Specifications of an LN

• Denier

• Filament: mono-/multi-filament

• Polymer type: polyester, polyethylene, polypropylene, ...

• Treatment technology

– Coating onto filaments

– Incorporated into filaments

1. Product description

….. specifications of an LN

• Identity test – usually a CIPAC method

• AI Content

– Be from a WHO compliant source

– g AI/kg ±25% (tolerance at ± 20 0C)

mg AI/m2 dose to remain constant, irrespective of denier

– Isomer ratio (range), if required

– Retention/release index

• % values, within a range

• Varies for different polymer/treatment technologies

• Content of synergist (g/kg ±25%)

• Retention/release index of synergist

• Relevant impurities (of manufacture or storage)

2. Active ingredient

3. Physical properties

• Netting mesh size

– Average no. and lowest value of complete holes/cm2

• Dimensional stability of netting to washing

– Not >5% shrinkage/expansion in either

dimensions

• Bursting strength (fabric & seams)

– Minimum & average b.s. (in kPa)

….. specifications of an LN

4. Storage stability

• After storage at elevated temperature, LN shall

comply with:

– Dimensional stability

– Bursting strength

– Wash resistance index

– Isomer ratio, if required

– Any by-products (relevant impurities)

• Temperature conditions:

Temp ± 2 0C 54 50 45 40 35 30

Weeks 2 4 6 8 12 18

….. specifications of an LN

What tests are not part of the

specifications, yet important?

• Flammability test

– 16CFR part 1610 (450 slanted test)

• results to be presented on the package

– EN 1102 (vertical test)

• Mass of netting (GSM)

– Weight in g/m2

– Specify GSM range for quality control

LNs in pipeline

Type Phase Brand Manufacturer

LNs

I Aka Net LN Kuse Lace Co., Japan

Panda Net 2.0 Life Ideas Textiles, China

MiraNet LN A to Z Textile Mills, Tanzania

Olyset Duo LN Sumitomo Chemical, Japan

II Yahe LN Fujian Yamei Industry, China

III DawaPlus 2.0 LN Tana Netting, UAE

Duranet LN Shobikaa Impex, India

LifeNet LN Bayer CropScience, France

Netprotect LN Intelligent Insect Control, France

Olyset Plus LN Sumitomo Chemical, Japan

PermaNet 3.0 LN Vestergaard Frandsen,

Switzerland

Kit for long-lasting

treatment of

mosquito nets

ICON MAXX Syngenta, Switzerland

Durability & flammability • Textile tests

– Fabric weight per unit area (EN ISO 12127)

– Bursting strength (EN ISO 13938-2)

– Bursting strength on seams (EN ISO 13938-2)

– Tear strength, length and width (EN ISO 13937-1)

– Tensile strength, length and width, with and without

hooks (ISO 13934-2)

– Flammability 16 CFR part 1610 and EN 1102

• Survivorship in operational use

WHOPES Guidelines: Efficacy assessment

Manual on specifications

• Provides the standard process, unified requirements and procedures, harmonized definitions and nomenclature, technical guidelines and standards applicable to pesticides for use in agriculture and public health.

• Developed through the FAO/WHO Joint Meeting on Pesticide Specifications (JMPS) through an open consultative process, including national programmes and representation by industry at JMPS meetings.

WWW.WHO.INT/WHOPES

LLIN Durability – Recommendations from WHO

Technical Expert Group on Malaria Vector Control

Malaria Policy Advisory Committee (MPAC)

Provides independent strategic advice and technical input to WHO for the development of policies related to malaria control and elimination

Malaria Policy Advisory Committee Evidence

Review

Groups

MPAC

RBM: Secretariat,

WGs and SRNs

WHO malaria policy

recommendations and

guidelines

WHO DG MoH and

NMCPs SAGE

JTEG (with

IVB)

VCAG

(with

NTD)

Standing TEG

Chemotherapy

ERG a

ERG b

ERG c

WHO GMP

Secretariat

WHO ROs

WHO COs

Other WHO

departments

Standing TEG

Drug

Resistance &

Containment

Standing TEG

Malaria

Vector

Control

Standing TEG

Surveillance,

Monitoring &

Evaluation

Technical Expert Group for Malaria Vector

Control

3 to 5 July, 2013

Estimating functional survival of

long-lasting insecticidal nets from field data

Proportional Hole Index to classify

nets into servicable and RRR

(rapid replacement required )

Insecticide retention no need to be

included

Two 75 denier polyester nets, both 3 years old

one serviceable, one "Triple R"

(Photos - Albert Kilian)

LLIN Durability – Recognition by

VCTEG

• Measurement of LLIN durability in

operational conditions using standardized

methods is important

• Better anticipation of the replacement

timing of nets in the field

• Encourage innovation, leading ultimately

towards LLINs with a lower cost per year of

protection

Operationalization of LLIN durability data

• WHOPES to consider including durability

(estimating median survival of LLINs) in the

criteria for LN specifications

• Will be in line with the testing of nets for

insecticide retention and if possible be

integrated into Phase 1 testing.

• However, WHO guidance will be required on

how to handle currently approved products

• Might lead to some LLINs being removed

from the recommended list if they fail to

meet the proposed WHO specifications

Best buy list:

• WHOPES recommendations focus on minimum

acceptable criteria

• the VCTEG recommends the launching of a systematic

system of performance assessment similar to the

successful experience made with Rapid Diagnostic Test

kits (FIND/CDC/WHO testing)

• This would allow purchasers to make a comparative cost-

benefit analysis in their purchasing options

• Ultimately stimulating manufacturers to produce and offer

more durable products with option to periodically

evaluate their newer versions/ products

• Future performance criteria could include insecticide

resistance management properties of candidate LLIN

products.

Call to countries and partners

• Quality field monitoring studies are needed

to inform procurement decisions and timing

the replacement of nets

• Countries and partners therefore need to

mobilize resources for:

– routine monitoring of LLIN durability under

operational use

– implementation research including capacity to

validate such data.

Thank you

Positions from which net pieces are cut for

chemical and biological assays

5

1 2

3

4

1

2

4

5

3

Rectangular net

Side panels -

Roof panel