Biodiversity of Mites in Dust of Poultry

Introduction

Around 20% population in India and abroad suffers from different allergy types like asthma etc. These mites are also of ecological importance. In the world 36 species of house dust Mite have been reported, out of which 29 have been reported from India. Some house dust mites found in the poultry dusts are allergens causing allergy in sensitive human beings. Some of them have also been found to cause diseases in poultry birds and poultry workers, and create ecological imbalance in nature. It may result into aerobio pollution problems. Hence this study was carried out at Pune. So far no work has been done in poultry mites and house dust mites in Pune district and the region around.

Material and Methods

Poultry Mites are the important materials found in poultry dusts, in atmosphere of the poultry farms at Ravet. The area is surrounded by agricultural land and very few houses. The site is located in Pimpri Chinchwad Corporation Pune. It is about 10 km away from PCMC area. The two poultry farms have been selected for the study, located about 100 meters apart.

Two methods were used for study of the mites.

Method # 1: Pick up method for isolation of mites from the poultry dust Fortnightly poultry dust was collected manually from different corners and central part of the poultry farms. The dust was sieved through a sieve with size of 300 mesh (Kashiram Maurya and Zafar Jamil). The sieved poultry dust sample was placed in Petri dish of 5.5cm diameter for microscopic examination. It was spread uniformly in thin layer. The mites were then picked up with the help of needle with its tip dipped in lactic acid. The picked mites were then stored in lactic acid in cavity blocks and were left overnight. Lactic acid was used for killing and clearing of mites and dissolution of cuticle thus making them transparent. The mites were then mounted on slides with ventral side up. It was mounted in the center over a clean slide in a drop of melted glycerin jelly. Total number of mites per gram of dust was determined fortnightly for one year and four months. Average number of mites per gram of dust was found out. Permanent slides were prepared and mites were observed under binocular research microscope for identification and to study biodiversity of mites in the poultry farms.

However quantification of mites and isolation by floatation technique after centrifugation could not be done during the course.

Method # 2: Determination of the number of mites in the poultry air Air sampling was carried out by volumetric Tilak Air Sampler continuously for one year and four months in both the poultry farms. Slides were prepared in melted glycerin jelly. These slides were then observed for quantification of mites in poultry atmosphere to carry out analysis of biodiversity of poultry mites.

Preparation of Glycerin Jelly:

• 300 ml distilled water was boiled in a beaker.

• 350 ml glycerin was added to it while boiling.

• 50 gm of gelatin powder was added in small portions with continuous stirring to avoid clump formation. The boiling was continued for 1 hour till the mixture became slightly yellowish color.

• 1 gm phenol was added to it, as a sterilizer. It was allowed to cool down for solidification at room temperature. It was used after melting whenever needed.

Observations and Results

The population pattern of various mites belonging to different Orders was observed. Six species of mites were observed in the poultry farms during these studies. About 200 specimens were screened to find out percentage contribution of each mite species. These studies revealed the incidence of Cheyletus eruditus (85%), Dermanyssus galinae(10%), Dermatophagoides farinae (05%), Dermatophagoides pteronyssinus(05%) and between June 2009 to November 2010. Subsequently few specimens of Pterolichus obtusus were reported in the poultry dusts which are under study.

Nutrition in Mites: It was found that species of Dermatophagoides feed by ingestion method on different fungal cultures. The mites were found to consume Aspergillus, Penicillium, Mucor, and Rhizopus fungi in cultures.

Life cycle in poultry mites

The average span of life in mite is up to 2-4 months. The mature male and female mites undergo mating by copulation. The mated female poultry mite lays totally 75-100 eggs in her life span. It lays the eggs singly or in groups of up to five eggs. After the completion of egg laying process female usually dies. Eggs are laid in poultry dusts. The eggs are oval, slightly elongated or cylindrical in shape. They are sclerotized and are about 50 micron in length. The eggs may hatch into larvae immediately after egg laying process depending upon favorable environmental conditions, or under unfavorable conditions, the egg may undergo diapause or rest only to hatch in next favorable season.

The hatched egg show clear marking of the cells running in longitudinal direction. The hatched larva is minute, oval to elongated grayish in color having three pairs of legs present ventrally on either side. It measures approximately 100 micron in length and 20 micron in width. It moults into deutonymph. It is bigger in size than larva but smaller than the adult. The deutonymph shows all four pairs of legs, which are smaller in length and not well developed. They have jointed legs. Mouth parts are not well developed. Male and female genital organs are not yet developed hence male and female specimen cannot be differentiated.

After few days deutonymph moults into tritonymph which is bigger than deutonymph with four pairs of elongated well developed legs present on the ventral side. It shows

development and differentiation of mouth parts and chelicerae. Genital organs could not be clearly visualized, hence male and female specimen cannot be distinguished. After its life span tritonymph moults into adult male or female, depending upon inborne sex in tritonymph. The male specimen shows developed male genital organ and sometimes hypertrophied pair of legs in some poultry mites, either first or third pair or some other male character like two pairs of genital papillae adanal suckers. With its skin ornamentation, sculpturing and orientation of setae (setation) differing in accordance with the species of poultry mites.

The adult female has all the four pairs alike without any hypertrophy and well developed female genital organ with itsspecific sculpturing and sclerotization of the skin and definite orientation of setae depending on the species of mite.

The life cycle of mite consists of mating by copulation, egg laying, hatching of egg into larva, which moult into nymphal stages like deutonymph and tritonymph ultimately developing into adult male or female ready for next mating. Thus poultry mite completes its life cycle within 2-4 months depending upon species.

Impact of environment on incidence of mites of poultry dusts:

Observations made during these studies indicated clearly that mite incidence varies according to variations in temperature, relative humidity and rainfall. It is found that higher RH around 80%, moderate temperature around 25°C and frequent rainfall acted as favourable conditions for incidence of mites and increase in population density hence there is progressive increase in number of mites per gram of poultry dusts from June to October because these congenial conditions existed during these months showing highest population of poultry mites during September and October.

Our findings revealed that low RH, high temperature, extremely cold condition and rainless days act as adverse condition for the incidence and growth of mites. Under these conditions, the mite population was significantly decreased between November to May that is comprising winter and summer season.

Discussion:

Very little work has been done on poultry mites and house dust mites in Pune region concerning the types of mites found in the poultry dust mites. In this we performed identification and presence of different types of mites in the poultry farms. During these studies 06 mites species were reported in different concentration of which Cheyletus eruditus (85%) was dominant followed by Dermanyssus galinae(10%), Dermatophagoides farinae(05%), Dermatophagoides pteronyssinus(05%) The presence of hatched eggs and the large number of mites that were present in the sample collected during rainy season reflects the behaviors and ecology of the mites. It was found that moderate temperature, high relative humidity provided most congenial environment for maximum percentage contribution of mites in the poultry dust. Relative Humidity effects the population of mites. This observation is also supported by Spieksma (1997). Whereas low temperature and high temperature were found unfavorable for the survival of mites as is revealed in cold dry winter months and hot summers of April and May. It is in agreement with those of Jogdand (2007). In the present study Dermanyssus was also found, which is the actual chicken mite. Hughes (1976) has found its distribution as cosmopolitan. Cheyletus eruditus was found in highest percentage contribution. Work on this species has also been done by Choudhary & Mukherjee (1971), and have recorded it as a common predating mite. The population of mites varied in different seasons.

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