*4.3.4. Ultrasound*

Ultrasound or sonography is a nondestructive method uses sound wave of >20 kHz to study the structure and secretions from brain. These wave with very short wavelength and low power density resolute every change in the brain without heating or cavitations effect [19]. Infection, swelling, lesions, or inflammation of the brain or the associated tissue can be clearly imaged. Despite these, over exposure to this wave may cause side effects like hearing loss and organ dysfunction.

## **4.4. Future directions**

A quick and specific diagnosis of any disease is necessary to initiate an early treatment against it. Present diagnostic methods for HME are inconclusive, time‐consuming, misleading, non‐specific, or complicated. Therefore, there is a need for a quick, simple, sensitive, and specific method for diagnosis of HME. Nowadays, several advanced methods have been developed for the diagnosis of different types of diseases. The principles of these methods can be used to develop a quick, simple, and reliable diagnostic method in future. Detection of any pathogen based on the analysis of partial or complete genome is one of the most preferred techniques nowadays. The genome of HSV is approximately of 152 kb which can be very easily analyzed as below:

#### *4.4.1. PCR*

Since the discovery of PCR, it is used as quick, specific, and sensitive method for diagnosis of several diseases. Several researchers proposed PCR‐based detection of HSV from patient samples through designing specific primers and found higher sensitive than other conventional methods [5, 20–22]. The PCR amplicons can be analyzed which is an agarose gel electrophoresis with or without Southern blotting [23], although Southern blotting increases the sensitivity of a PCR but increase the time taken. Therefore, some researchers replaced it with enzyme‐linked inmmunosorbent assay. Recently, we have reported very less time‐consuming direct PCR for detection of *Neisseria meningitidis* from the CSF samples (**Figure 1**) [24, 25]. The same procedure may be followed to detect HSV in future.

#### *4.4.2. Biosensors*

Biosensors are replacing the traditional diagnostic methods because of their sensitivity, specificity, simplicity, and economical value [26–29]. A biosensor contains a biotransducer or bioreceptor which interact with the analyte, and the signal released is detected by a detector. At a low analyte concentration, electrochemical sensor is more favorable than the others (**Figure 2**) [28, 29]. For construction of an electrochemical sensor, ionic bonding between the gold and thiol‐group can be used for immobilization. Which can be further hybridized with the complementary analyte and detected electrochemically (**Figure 3**) [28, 29]. Metallic nanoparticles and carbon nanotubes can also be used to increase the surface of immobilization and sensitivity of the sensor for quick, sensitive, and specific diagnosis of large number of HME suspected samples at a time [30, 31].

**Figure 1.** PCR‐based diagnosis of bacterial meningitis Lane 1 and 2: control, lane 10, 16, and 26: infected patients, and lane 3‐9, 11‐15, 17‐25, and 12‐20: negative [25].

**Figure 2.** Schematic representation of immobilization of thiol‐labeled probe onto gold electrode and detection of *N. meningitidis* from patient CSF [29].

Herpes Meningoencephalitis: Causes, Diagnosis, and Treatment http://dx.doi.org/10.5772/intechopen.68553 55

**Figure 3.** Schematic representation of immobilization of probe on nanocomposite and diagnosis of bacterial meningitis from patient CSF [30].

#### *4.4.3. Microarray*

*4.4.2. Biosensors*

samples at a time [30, 31].

lane 3‐9, 11‐15, 17‐25, and 12‐20: negative [25].

from patient CSF [29].

Biosensors are replacing the traditional diagnostic methods because of their sensitivity, specificity, simplicity, and economical value [26–29]. A biosensor contains a biotransducer or bioreceptor which interact with the analyte, and the signal released is detected by a detector. At a low analyte concentration, electrochemical sensor is more favorable than the others (**Figure 2**) [28, 29]. For construction of an electrochemical sensor, ionic bonding between the gold and thiol‐group can be used for immobilization. Which can be further hybridized with the complementary analyte and detected electrochemically (**Figure 3**) [28, 29]. Metallic nanoparticles and carbon nanotubes can also be used to increase the surface of immobilization and sensitivity of the sensor for quick, sensitive, and specific diagnosis of large number of HME suspected

54 Meningoencephalitis - Disease Which Requires Optimal Approach in Emergency Manner

**Figure 2.** Schematic representation of immobilization of thiol‐labeled probe onto gold electrode and detection of *N. meningitidis*

**Figure 1.** PCR‐based diagnosis of bacterial meningitis Lane 1 and 2: control, lane 10, 16, and 26: infected patients, and

Microarray involves immobilization of an array of single or multiple types of ssDNA probes onto a surface and then hybridization with complementary ssDNA followed by detection through LASER scanning. Microarray is an advance and promising technique for diagnosis of any disease [32]. Tong et al. first time used 16S microarray for detection of neonatal bacterial meningitis using patient's blood [33]. Nowadays, DNA microarray is used for detection of large number of suspected samples of different diseases at a time. DNA microarray can either be constructed by direct synthesis of oligonucleotide on the solid surface (affymetrix microarray) or by immobilization of earlier synthesized oligonucleotides onto a substrate [34]. The second one remains as choice of preference for the researchers because of its flexibility regarding the surface and ligand used for construction of microarray [35]. Glasses are preferred over other platforms due to their low‐cost, intrinsic fluorescence, and superior optical properties. 3′‐modified probe is preferred over the 5′‐modified probe because the later requires phosphoramidite reagents of the modifier in strictly anhydrous condition [36]. Surface of the substrates can be coated with polylysine or aminopropyle to increase the immobilization. The noncovalent attachments used for immobilization of the ssDNA probe onto an electrode are epoxide‐amine, epoxide‐ thiol, epoxide‐aminooxyalkyl, aldehyde‐amine, and semicarbazide‐aldehyde. Carboxyl‐amine, thiol‐disulfide, biotin‐streptavidin, gold‐thiol, zirconylated‐surface‐phosphate, and epoxide‐ amine are some of the covalent linkage used often for the probe immobilization (**Figure 4**) [34]. The immobilization of the probe is optimized for time, pH, temperature, and concentration in order to obtain maximum immobilization efficiency. The array of immobilized oligomers can be hybridized with the genomic DNA of pathogen in patient sample. Several researches have been reported by our lab to detect the presence of *N. meningitidis* from the CSF samples using microarray [35, 36]. The same principle can be used to develop a microchip in future for diagnosis of large number of HME suspected samples at a time.

**Figure 4.** Schematic presentation of microarray‐based detection of bacterial meningitis [35].
