Factors Influencing the Performance of the Precipitin Test in the Determination of Blood Meals of Insects

A sandwich enzyme-linked immunosorbent assay (ELISA) test was developed to detect blood-meals in insects and identify the host fed on. The test proved both sensitive and specific. Very small quantities of fresh blood (about 0-02 fjd) can be detected; in practice, this enables blood in mosquitoes which are about three-quarters gravid to be identified. In trials in both Zambia and Britain, positive reactions were easily identified visually; consequently, this enabled the ELISA technique to be used as a routine field test. In addition to those of mosquitoes, blood-meals of a few Culicoides species were also successfully identified.

Section: Sensitivitysupporting

confidence: 67%

The enzyme-linked immunosorbent assay (ELISA) test for the identification of blood-meals of haematophagous insects

Service

Voller

Bidwell

1986

“…Several methods of collecting and storing predators have been used. A very convenient method, which allows easy transport of material, is to smear the gut contents onto filter paper, but it is known that proteins tend to bind to cellulose and it may be difficult to elute all the protein if the samples are stored for long periods (Eligh, 1952). Good quality paper such as Whatman No.…”

Section: Collection and Preparation Of Predatorsmentioning

confidence: 99%

The use of serology in evaluating invertebrate prey-predator relationships : a review

Boreham

Ohiagu

1978

Several methods, including the use of seralogy, are available for evaluating prey-predator relationships. Two basic methods involving precipitation and agglutination reactions have been utilised, both of which depend on the production of specific antisera with high titres. A critical account is presented of methods of preparing an'tisera, with particular reference to the amount of antigen required, the route of inoculation and testing antisera, together with a review of the five precipitation and two agglutination techniques available. The main limitations of A 1 7 2 p -F -L -BOREHAM and C. E. OHIAGU serological methods are the specificity of the arttisera and the difficulties in quantifying results unless assumptions are made as to the number of prey eaten at each feed. Details of studies employing serological techniques to identify the predators of specific prey and the food of invertebrates are given in two tables. The value of serological techniques is discussed in relation to the ecology of invertebrates by considering, as examples, the insect fauna on broom (Sarothamnus scoparius), predation of mosquitoes and the food of triclads. Errors in the quantification of predation may occur by including positive reactions resulting from carrion feeding or material ingested accidentally on plants by phytophagous arthropods.

“…The sensitivity of the latex agglutination test was slightly less than that of the precipitin test. The method of extraction of blood-meals, as used here, has little effect on the sensitivity of the test, but it has been shown that under certain circumstances some protein is 'bound to filter paper and cannot toe eluted (Eligh, 1952). When attempts to isolate viruses are to be undertaken, it will toe necessary to use whole insects rather than squashes, since this is less likely to cause denaturation of the virus.…”

Section: Discussionmentioning

confidence: 99%

A latex agglutination test for the identification of blood-meals ofCulicoides(Diptera: Ceratopogonidae)

Boorman

Mellor

Boreham

et al. 1977

A latex agglutination test to identify the sources of blood-meals of Culicoides is described. The method requires the minimum amounts of reagents and apparatus and would be suitable for rapid tests under field conditions. Blood-meals of Culicoides nubeculosus (Mg.) and C. variipennis (Coq.) from laboratory cultures, which had engorged on blood from several species of domestic animals, were differentiated without difficulty. In a series of ' blind' tests, the blood-meals of 49 C. variipennis from seven species of domestic animal were identified with 100% accuracy. The differentiation of blood-meals from closely related hosts, such as mouse and guineapig or ox and sheep, is entirely dependent upon the specificity of the antisera conjugated to the latex. Blood-meals could be identified reliably for aibout 48 h after ingestion at 20-25 °C, but at higher temperatures the reaction became less reliable after 24 h. Detergents commonly used in collecting midges had no effect on the latex agglutination test, but 0-01% merthiolate, often used as a preservative, caused auto-agglutination and cannot be used when this test is to be applied.